[X86] Adding fp128 support for strict fcmp

Summary: Adding fp128 support for strict fcmp

Reviewers: craig.topper, LiuChen3, andrew.w.kaylor, RKSimon, uweigand

Subscribers: hiraditya, llvm-commits, LuoYuanke

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71897