[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.

libunwind/include/CMakeLists.txt

@@ -3,7 +3,6 @@ set(files
     libunwind.h
     libunwind.modulemap
     mach-o/compact_unwind_encoding.h
-    mach-o/compact_unwind_encoding.modulemap
     unwind_arm_ehabi.h
     unwind_itanium.h
     unwind.h

libunwind/include/mach-o/compact_unwind_encoding.modulemap

@@ -1,4 +0,0 @@
-module MachO.compact_unwind_encoding [system] {
-  header "compact_unwind_encoding.h"
-  export *
-}