Fix test that wasn't testing anything
Fix test that was not being run
Make test run reliably

llc waits for input on stdin, which was not provided in this test. It
was running only thanks to a quirk in the way lit concatenates
commands.
Fix a test that was never being run, mark it XFAIL

Turns out this has always been crashing since the test landed in
r186647:

  Assertion failed: (Access != AS_none && "Access specifier is AS_none inside a record decl"), function CheckAccessDeclContext, file clang/lib/AST/DeclBase.cpp, line 690.

Needs attention.