Don't drop windows.winmd when packaging Windows toolchain

It is needed for UWP build and is the same on at least 2 machines in
C:\Program Files (x86)\Windows Kits\10\UnionMetadata\10.0.18362.0\Windows.winmd

Bug: chromium:1032635
Change-Id: I9d7148a8dc11ea85f1b930f63ae19eaa58ac2bf6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2007881
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>

win_toolchain/package_from_installed.py

@@ -248,16 +248,14 @@ def BuildFileList(override_dir, include_arm):
                      os.path.join(dest_dir, system_crt_file)))
 
   # Generically drop all arm stuff that we don't need, and
-  # drop .msi files because we don't need installers, and drop windows.winmd
-  # because it is unneeded and is different on every machine and drop
+  # drop .msi files because we don't need installers and drop
   # samples since those are not used by any tools.
   def is_skippable(f):
     return ('arm\\' in f.lower() or
             (not include_arm and 'arm64\\' in f.lower()) or
             'samples\\' in f.lower() or
             f.lower().endswith(('.msi',
-                                '.msm',
-                                'windows.winmd')))
+                                '.msm')))
   return [(f, t) for f, t in result if not is_skippable(f)]
 
 def GenerateSetEnvCmd(target_dir):