Revert r159588, and apply a more principled fix. Place the fix for this

in the abstraction for lit test suites so that the various other layers
of abstraction pick up the same behavioral fix, and so that we still get
a complete list of dependencies for the 'check-all' target.

This should fix the follow-on issues of the same nature with various
other build targets, including Clang targets. Sorry for the churn, and
again thanks to Matt for testing and breaking this more thoroughly.

llvm-svn: 159593