tests: assume the hooks are disabled by default

tests: assume the hooks are disabled by default

Stop moving the .git/hooks directory out of the way, or creating it
during test setup. Instead assume that it will contain
harmless *.sample files.

That we can assume that is discussed in point #4 of
f0d4d398e28 (test-lib: split up and deprecate test_create_repo(),
2021-05-10), those parts of this could and should have been done in
that change.

Removing the "mkdir -p" here will then validate that our templates are
being used, since we'd subsequently fail to create a hook in that
directory if it didn't exist. Subsequent commits will have those hooks
created by a "test_hook" wrapper, which will then being doing that
same validation.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>