tests: ensure run-tests handles multiple lines of churn 1ad0ddf8cccc added the ability to remember lines (including their flags, like glob) and tolerate them even if the output order varies. This test ensures that the code will continue to work in the future.

subrepo: adapt to git's recent renames-by-default Git turned on renames by default in commit 5404c11 (diff: activate diff.renames by default, 2016-02-25). The change is destined for release in git 2.8.0. The change breaks test-subrepo-git, which test specifically that a moved file is reported as a removal and an addition. Fix by passing --no-renames (available in git since mid 2006) to the diff commands that don't use --quiet (should make no difference for those).