MFC Clang debuginfo crash fix

r271432: Merge upstream Clang rev 205331 debuginfo crash fix:

      Debug info: fix a crash when emitting IndirectFieldDecls, which were
      previously not handled at all.
      rdar://problem/16348575

r271433: Add clang patch corresponding to r271432

Approved by:	re
Sponsored by:	DARPA, AFRL