[LibCallsShrinkWrap] Set IsFPConstrained is true for creating quiet floating...

[LibCallsShrinkWrap] Set IsFPConstrained is true for creating quiet floating comparision if function has strictfp attribute

Create a quiet floating-point comparision if function has strictfp attribute.
Avoid unexpected FP exception raised during libcall domain error checking.
It raises an FP exception only in case where an input is a signaling NaN.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D152776