tests: diff -r on Solaris emits "Common subdirectories:" When using the -r option to Solaris diff, any directores that compare identically are mentioned in the output. We don't really care about these directories for the purposes of this test, so ignore them.

tests: work around differing hunk headers between GNU and Solaris diff The hunk headers specifying what lines the hunk apply to differ. They're irrelevant to the test, so just eliminate them from the output.