Make lldbinline.py regenerate the Makefile each time it builds.

If a lldbinline test's source file changed language, then the Makefile wasn't
updated.  This was a problem if the Makefile was checked into the repository.

Now lldbinline.py always regenerates the Makefile and asserts if the
newly-generated version is not the same as the one already there.  This ensures
that the repository will never be out of date without a buildbot failing.

http://reviews.llvm.org/D21032

llvm-svn: 272024