[StrictFP][IPSCCP] Constant fold intrinsics with metadata arguments

This teaches the SCCP Solver how to constant fold more intrinsics. Constant
folding appears to be just as good as D115737 but much, much lower in code
change impact as suggested by nikic.

The constrained floating-point intrinsics all take at least one metadata
argument and were the motivation for the change.

Differential Revision: https://reviews.llvm.org/D136466