Bug 1675370: Mark /ipc/mscom as exclusive to Windows; r=firefox-build-system-reviewers,dmajor

Differential Revision: https://phabricator.services.mozilla.com/D95925

ipc/mscom/moz.build

@@ -90,3 +90,4 @@ FINAL_LIBRARY = "xul"
 
 with Files("**"):
     BUG_COMPONENT = ("Core", "IPC: MSCOM")
+    SCHEDULES.exclusive = ["windows"]