"This fixes message sends to super in a way that both works with real code and passes the test in the test suite.  It also fixes a crash when using recent versions of GNU libobjc and compiling modules that do not contain any constant strings but do contain a declaration of the constant string class and possible some other corner cases (thanks to Pete French for providing me with a test case for that one)."

Patch by David Chisnall!

llvm-svn: 70093