[multiversion] Update Clang for the API change in LLVM r227731.

This moves all of the PassManager <-> Target communication to use the
new pass manager's TargetIRAnalysis even with the old pass manager. See
the LLVM commit for some of why things are moving in this direction, but
the short version is that this will enable us to create per-function
TargetTransformInfo objects that have correct subtarget information for
that function.

llvm-svn: 227732