[libc] Return correct values for hypot when overflowed.

Hypot incorrectly returns +Inf when overflowed with FE_DOWNWARD and
FE_TOWARDZERO rounding modes.

Reviewed By: sivachandra, zimmermann6

Differential Revision: https://reviews.llvm.org/D133370

GitOrigin-RevId: bb6966aa5340609dc5144b9f496f548bc53f7e60
2 files changed