[libc][math] Refactor round-roundeven-trunc family to header-only (#195590)
Refactors the round-roundeven-trunc math family to be header-only.
part of: #147386
Target Functions:
- round
- roundbf16
- roundf
- roundf128
- roundf16
- roundl
- roundeven
- roundevenbf16
- roundevenf
- roundevenf128
- roundevenf16
- roundevenl
- trunc
- truncbf16
- truncf
- truncf128
- truncf16
- truncl