swift234

Unbork Xcode CMake Release and RelWithDebInfo builds.

...at the cost of a zillion warnings about identical Makefile commands.
I'm not entirely sure what's up with this, since they should apply to
different configurations.

Somewhere along the way, an extra "Debug" or "Release" started getting
mangled into the path for Swift libraries, which is already within a
"Debug"/"Release" directory. Someone (Joe?) had already countered this
for "Debug", but not for any other configurations. This wasn't being
noticed because it would fall back to the old libraries unless you
cleared out your build directory.

While here, add swiftFoundation as a test dependency when we have a
MODULES_SDK set.

Swift SVN r4827