fs: fix parsing of times and durations of the form "YYYY-MM-DD HH:MM:SS"

Before this fix, the parsing code gave an error like this

    parsing "2022-08-02 07:00:00" as fs.Time failed: expected newline

This was due to the Scan call failing to read all the data.

This patch fixes that, and redoes the tests

fs/parsetime.go

@@ -83,7 +83,7 @@ func (t *Time) UnmarshalJSON(in []byte) error {
 
 // Scan implements the fmt.Scanner interface
 func (t *Time) Scan(s fmt.ScanState, ch rune) error {
-	token, err := s.Token(true, nil)
+	token, err := s.Token(true, func(rune) bool { return true })
 	if err != nil {
 		return err
 	}