Don't run dwo tests for windows targets.

-gsplit-dwarf is not implemented by clang on Windows.  As such,
all the dwo tests are having the -gsplit-dwarf command line option
completely ignored, and the result is you get regular dwarf debug
information, and it's just running the exact same tests twice,
doubling the length of the test suite for no good reason.

llvm-svn: 257363

lldb/packages/Python/lldbsuite/test/test_categories.py

@@ -44,7 +44,8 @@ def unique_string_match(yourentry, list):
 
 def is_supported_on_platform(category, platform):
     if category == "dwo":
-        return platform in ["linux", "freebsd", "windows"]
+        # -gsplit-dwarf is not implemented by clang on Windows.
+        return platform in ["linux", "freebsd"]
     elif category == "dsym":
         return platform in ["darwin", "macosx", "ios"]
     return True