8050825: Support running regression tests using jtreg_tests+TESTDIRS from top level
Reviewed-by: dholmes, mduigou
^build/
^dist/
/nbproject/private/
^src/share/tools/hsdis/build/
^src/share/tools/IdealGraphVisualizer/[a-zA-Z0-9]*/build/
^src/share/tools/IdealGraphVisualizer/build/
^src/share/tools/IdealGraphVisualizer/dist/
^.hgtip
.DS_Store