[lit] Only update specific fields from remote test object

Don't update whole test object from the remote (pickled) finished test
object.  Doing so also changes the config and suite members, which we
want to avoid.

llvm/utils/lit/lit/run.py

@@ -99,9 +99,11 @@ def _wait_for(self, async_results, deadline):
 
     # Update local test object "in place" from remote test object.  This
     # ensures that the original test object which is used for printing test
-    # results reflect the changes.
+    # results reflects the changes.
     def _update_test(self, local_test, remote_test):
-        local_test.__dict__.update(remote_test.__dict__)
+        # Needed for getMissingRequiredFeatures()
+        local_test.requires = remote_test.requires
+        local_test.result = remote_test.result
 
     # TODO(yln): interferes with progress bar
     # Some tests use threads internally, and at least on Linux each of these