[libunwind] Stop installing the mach-o module map (#105616)

libunwind shouldn't know that compact_unwind_encoding.h is part of a
MachO module that it doesn't own. Delete the mach-o module map, and let
whatever is in charge of the mach-o directory be the one to say how its
module is organized and where compact_unwind_encoding.h fits in.

GitOrigin-RevId: 172c4a4a147833f1c08df1555f3170aa9ccb6cbe