t6038: make tests fail for the right reason

t6038 had a pair of tests that were expected to fail, but weren't failing for the expected reason. Both were meant to do a merge that could be done cleanly after renormalization, but were supposed to fail for lack of renormalization. Unfortunately, both tests had staged changes, and checkout -m would abort due to the presence of those staged changes before even attempting a merge. Fix this first issue by utilizing git-restore instead of git-checkout, so that the index is left alone and just the working directory gets the changes we want. However, there is a second issue with these tests. Technically, they just wanted to verify that after renormalization, no conflicts would be present. This could have been checked for by grepping for a lack of conflict markers, but the test instead tried to compare the working directory files to an expected result. Unfortunately, the setting of "text=auto" without setting core.eol to any value meant that the content of the file (in particular, the line endings) would be platform-dependent and the tests could only pass on some platforms. Replace the existing comparison with a call to 'git diff --no-index --ignore-cr-at-eol' to verify that the contents, other than possible carriage returns in the file, match the expected results and in particular that the file has no conflicts from the checkout -m operation. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>