[libc] Add implementation for hypotf

Truncating the sum of squares, and then use shift-and-add algorithm to compute its square root.
Required MPFR testing infra is updated in https://reviews.llvm.org/D87514

Differential Revision: https://reviews.llvm.org/D87516

GitOrigin-RevId: f55963d501e46c9453d08a0c764ec40141230966
9 files changed