[VP] Binary floating-point intrinsics.

This patch implements vector-predicated intrinsics on IR level for fadd,
fsub, fmul, fdiv and frem.  There operate in the default floating-point
environment. We will use constrained fp operand bundles for constrained
vector-predicated fp math (D93455).

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D93470