Exclude compiler_rt_shims.cpp

We have excluded files in
https://github.com/emscripten-core/emscripten/tree/main/system/lib/libcxx/src/support/win32.
This is a new file added in this directory in
llvm/llvm-project#83575.

Author: aheejin

tools/system_libs.py

@@ -1653,11 +1653,13 @@ class libcxx(NoExceptLibrary, MTLibrary):
     'xlocale_zos.cpp',
     'mbsnrtowcs.cpp',
     'wcsnrtombs.cpp',
+    'int128_builtins.cpp',
+    'libdispatch.cpp',
+    # Win32-specific files
     'locale_win32.cpp',
     'thread_win32.cpp',
     'support.cpp',
-    'int128_builtins.cpp',
-    'libdispatch.cpp',
+    'compiler_rt_shims.cpp',
     # Emscripten does not have C++20's time zone support which requires access
     # to IANA Time Zone Database. TODO Implement this using JS timezone
     'tz.cpp',