[cxxmodules] Removed `libXXX.so` from C++ module names.
[cxxmodules] Removed `libXXX.so` from C++ module names.

The Core module is now just called `Core`, and no longer `libCore.so`,
which leads to the confusing PCM file name `libCore.so.pcm` which is 75%
just boilerplate prefixes and suffixes. This also make the error
messages from clang more readable now as they use the same module name.

root-mirror/root,zzxuanyuan/root,karies/root,karies/root,root-mirror/root,zzxuanyuan/root,root-mirror/root,zzxuanyuan/root,karies/root,karies/root,olifre/root,olifre/root,root-mirror/root,olifre/root,zzxuanyuan/root,zzxuanyuan/root,karies/root,zzxuanyuan/root,karies/root,karies/root,zzxuanyuan/root,olifre/root,karies/root,olifre/root,zzxuanyuan/root,root-mirror/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,zzxuanyuan/root,zzxuanyuan/root,zzxuanyuan/root,olifre/root,olifre/root,zzxuanyuan/root,root-mirror/root,olifre/root,root-mirror/root,root-mirror/root,olifre/root,karies/root,root-mirror/root,karies/root,karies/root