AutoUpgrade: upgrade from scalar TBAA format to struct-path aware TBAA format.

We treat TBAA tags as struct-path aware TBAA format when the first operand
is a MDNode and the tag has 3 or more operands.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191593 91177308-0d34-0410-b5e6-96231b3b80d8