[DAGCombiner] Fold 0 div/rem X to 0

Reviewers: RKSimon, spatel, javed.absar, craig.topper, t.p.northover

Reviewed By: RKSimon

Subscribers: craig.topper, llvm-commits

Differential Revision: https://reviews.llvm.org/D52504

llvm-svn: 345721