bisync: equality check before renaming (leave identical files alone)

Improved detection of false positive change conflicts (identical files are now left alone instead of renamed)
https://forum.rclone.org/t/bisync-bugs-and-feature-requests/37636#:~:text=1.%20Identical%20files%20should%20be%20left%20alone%2C%20even%20if%20new/newer/changed%20on%20both%20sides

cmd/bisync/testdata/test_equal/golden/_testdir_path1.._testdir_path2.copy1to2.que

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+"file1.txt..path1"

cmd/bisync/testdata/test_equal/golden/_testdir_path1.._testdir_path2.copy2to1.que

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+"file1.txt..path2"

cmd/bisync/testdata/test_equal/golden/_testdir_path1.._testdir_path2.path1.lst

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+# bisync listing v1 from test
+-      109 md5:294d25b294ff26a5243dba914ac3fbf7 - 2000-01-01T00:00:00.000000000+0000 "RCLONE_TEST"
+-       33 md5:ea683c03f780b76a62405456b08ae6fd - 2001-03-04T00:00:00.000000000+0000 "file1.txt..path1"
+-       33 md5:2b4975bb20f7be674e66d78570ba2fb1 - 2001-01-02T00:00:00.000000000+0000 "file1.txt..path2"
+-       37 md5:9fe822ddd1cb81d83aae00fa48239bd3 - 2001-01-02T00:00:00.000000000+0000 "file2.txt"

cmd/bisync/testdata/test_equal/golden/_testdir_path1.._testdir_path2.path1.lst-new

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+# bisync listing v1 from test
+-      109 md5:294d25b294ff26a5243dba914ac3fbf7 - 2000-01-01T00:00:00.000000000+0000 "RCLONE_TEST"
+-       33 md5:ea683c03f780b76a62405456b08ae6fd - 2001-03-04T00:00:00.000000000+0000 "file1.txt"
+-       37 md5:9fe822ddd1cb81d83aae00fa48239bd3 - 2001-01-02T00:00:00.000000000+0000 "file2.txt"

cmd/bisync/testdata/test_equal/golden/_testdir_path1.._testdir_path2.path2.lst

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+# bisync listing v1 from test
+-      109 md5:294d25b294ff26a5243dba914ac3fbf7 - 2000-01-01T00:00:00.000000000+0000 "RCLONE_TEST"
+-       33 md5:ea683c03f780b76a62405456b08ae6fd - 2001-03-04T00:00:00.000000000+0000 "file1.txt..path1"
+-       33 md5:2b4975bb20f7be674e66d78570ba2fb1 - 2001-01-02T00:00:00.000000000+0000 "file1.txt..path2"
+-       37 md5:9fe822ddd1cb81d83aae00fa48239bd3 - 2001-01-02T00:00:00.000000000+0000 "file2.txt"

cmd/bisync/testdata/test_equal/golden/_testdir_path1.._testdir_path2.path2.lst-new

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+# bisync listing v1 from test
+-      109 md5:294d25b294ff26a5243dba914ac3fbf7 - 2000-01-01T00:00:00.000000000+0000 "RCLONE_TEST"
+-       33 md5:2b4975bb20f7be674e66d78570ba2fb1 - 2001-01-02T00:00:00.000000000+0000 "file1.txt"
+-       37 md5:9fe822ddd1cb81d83aae00fa48239bd3 - 2001-01-02T00:00:00.000000000+0000 "file2.txt"

cmd/bisync/testdata/test_equal/golden/test.log

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+(01)  : test equal
+
+
+(02)  : test initial bisync
+(03)  : bisync resync
+INFO  : Synching Path1 "{path1/}" with Path2 "{path2/}"
+INFO  : Copying unique Path2 files to Path1
+INFO  : Resynching Path1 to Path2
+INFO  : Resync updating listings
+INFO  : Bisync successful
+
+(04)  : test changed on both paths and NOT identical - file1 (file1R, file1L)
+(05)  : touch-glob 2001-01-02 {datadir/} file1R.txt
+(06)  : copy-as {datadir/}file1R.txt {path2/} file1.txt
+(07)  : touch-glob 2001-03-04 {datadir/} file1L.txt
+(08)  : copy-as {datadir/}file1L.txt {path1/} file1.txt
+
+(09)  : test changed on both paths and identical - file2
+(10)  : touch-glob 2001-01-02 {datadir/} file2.txt
+(11)  : copy-as {datadir/}file2.txt {path1/} file2.txt
+(12)  : copy-as {datadir/}file2.txt {path2/} file2.txt
+
+(13)  : test bisync run
+(14)  : bisync
+INFO  : Synching Path1 "{path1/}" with Path2 "{path2/}"
+INFO  : Path1 checking for diffs
+INFO  : - Path1    File is newer                       - file1.txt
+INFO  : - Path1    File is newer                       - file2.txt
+INFO  : Path1:    2 changes:    0 new,    2 newer,    0 older,    0 deleted
+INFO  : Path2 checking for diffs
+INFO  : - Path2    File is newer                       - file1.txt
+INFO  : - Path2    File is newer                       - file2.txt
+INFO  : Path2:    2 changes:    0 new,    2 newer,    0 older,    0 deleted
+INFO  : Applying changes
+INFO  : Checking potential conflicts...
+ERROR : file1.txt: md5 differ
+NOTICE: Local file system at {path2}: 1 differences found
+NOTICE: Local file system at {path2}: 1 errors while checking
+NOTICE: Local file system at {path2}: 1 matching files
+INFO  : Finished checking the potential conflicts. 1 differences found
+NOTICE: - WARNING  New or changed in both paths        - file1.txt
+NOTICE: - Path1    Renaming Path1 copy                 - {path1/}file1.txt..path1
+NOTICE: - Path1    Queue copy to Path2                 - {path2/}file1.txt..path1
+NOTICE: - Path2    Renaming Path2 copy                 - {path2/}file1.txt..path2
+NOTICE: - Path2    Queue copy to Path1                 - {path1/}file1.txt..path2
+NOTICE: - WARNING  New or changed in both paths        - file2.txt
+INFO  : Files are equal! Skipping: file2.txt
+INFO  : - Path2    Do queued copies to                 - Path1
+INFO  : - Path1    Do queued copies to                 - Path2
+INFO  : Updating listings
+INFO  : Validating listings for Path1 "{path1/}" vs Path2 "{path2/}"
+INFO  : Bisync successful

cmd/bisync/testdata/test_equal/initial/RCLONE_TEST

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+This file is used for testing the health of rclone accesses to the local/remote file system.  Do not delete.

cmd/bisync/testdata/test_equal/modfiles/file1L.txt

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+This file is NOT identical to 1R

cmd/bisync/testdata/test_equal/modfiles/file1R.txt

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+This file is NOT identical to 1L

cmd/bisync/testdata/test_equal/modfiles/file2.txt

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+This file is identical on both sides

cmd/bisync/testdata/test_equal/scenario.txt

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+test equal
+# Check that changed files on both sides are renamed ONLY if not-identical
+# See: https://forum.rclone.org/t/bisync-bugs-and-feature-requests/37636#:~:text=1.%20Identical%20files%20should%20be%20left%20alone%2C%20even%20if%20new/newer/changed%20on%20both%20sides
+# - Changed on Path2 and on Path1, and NOT identical       file1 (file1r, file1l)
+# - Changed on Path2 and on Path1, and identical           file2
+
+test initial bisync
+bisync resync
+
+test changed on both paths and NOT identical - file1 (file1R, file1L)
+touch-glob 2001-01-02 {datadir/} file1R.txt
+copy-as {datadir/}file1R.txt {path2/} file1.txt
+touch-glob 2001-03-04 {datadir/} file1L.txt
+copy-as {datadir/}file1L.txt {path1/} file1.txt
+
+test changed on both paths and identical - file2
+touch-glob 2001-01-02 {datadir/} file2.txt
+copy-as {datadir/}file2.txt {path1/} file2.txt
+copy-as {datadir/}file2.txt {path2/} file2.txt
+
+test bisync run
+bisync