Fix TBAA: Set path tag metadata to instruction.

This commit replace the old createTBAANode() with the
struct-path TBAA introduced after LLVM 3.3.

This should fix the possible regression after merging LLVM 3.4.

Change-Id: Ie21fe4616784bad467b0f20226fce48da3afb2bd
Merge "Fix TBAA: Set path tag metadata to instruction."