Fix aliasing of launder.invariant.group

Summary:
Patch for capture tracking broke
bootstrap of clang with -fstict-vtable-pointers
which resulted in debbugging nightmare. It was fixed
https://reviews.llvm.org/D46900 but as it turned
out, there were other parts like inliner (computing of
noalias metadata) that I found after bootstraping with enabled
assertions.

Reviewers: hfinkel, rsmith, chandlerc, amharc, kuhar

Subscribers: JDevlieghere, eraman, llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D47088

llvm-svn: 333070