t4014: treat rev-list output as the expected value

t4014: treat rev-list output as the expected value

In 6bd26f58ea (t4014: use test_line_count() where possible, 2019-08-27),
we converted many test cases to take advantage of the test_line_count()
function. In one conversion, we inverted the expected and actual value
as tested by test_line_count(). Although functionally correct, if
format-patch ever produced incorrect output, the debugging output would
be a bunch of hashes which would be difficult to debug.

Invert the expected and actual values provided to test_line_count() so
that if format-patch produces incorrect output, the debugging output
will be a list of human-readable files instead.

Helped-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>