t6031-merge-recursive: More fixes for exec bit challenged filesystems
Commit
28f880241782024ecb212f1641c8dc487124523b improved the tests to
work on filesystems that do not honor the exec bit, but it didn't go the
full nine yards: If chmod +x does not work, then test -x will not work
reliably, either, which was the only way how the tests checked the result.
This patch works around the issue by testing the index if the filesystem
does not report that the exec bit is set.
Signed-off-by: Johannes Sixt <j6t@kdbg.org>