[PATCH] Revert "[SCEV] add no wrap flag for SCEVAddExpr."

[PATCH] Revert "[SCEV] add no wrap flag for SCEVAddExpr."

This reverts r366419 because the analysis performed is within the context of
the loop and it's only valid to add wrapping flags to "global" expressions if
they're always correct.

llvm-svn: 373184
(cherry picked from commit 58e8c793d0e43150a6452e971a32d7407a8a7401)

Gbp-Pq: Name 373184.patch