test: remove a porcelain test that hard-codes commit names

test: remove a porcelain test that hard-codes commit names

The rev-list output in this test depends on the details of test_tick's
dummy dates and the choice of hash function.  Worse, it depends on the
order and nature of commits made in the earlier tests, so adding new
tests or rearranging existing ones breaks it.

It would be nice to check that "git commit" and commit-tree name
objects consistently and that commit objects' text is as documented,
but this particular test checks everything at once and hence is not a
robust test for that.  Remove it.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>