Run desktop darwin tests in debug mode (flutter#21660)

Author: iskakaushik

testing/run_tests.py

@@ -148,6 +148,11 @@ def RunCCTests(build_dir, filter):
   if IsMac():
     RunEngineExecutable(build_dir, 'flutter_channels_unittests', filter, shuffle_flags)
 
+  # These tests can only be run on Darwin on debug mode.
+  # See: https://github.com/flutter/flutter/issues/66664
+  if IsMac() and ('debug' in build_dir):
+    RunEngineExecutable(build_dir, 'flutter_desktop_darwin_unittests', filter, shuffle_flags)
+
   # https://github.com/flutter/flutter/issues/36296
   if IsLinux():
     RunEngineExecutable(build_dir, 'txt_unittests', filter, shuffle_flags)