bpo-37531: Fix regrtest timeout for subprocesses (GH-15072)

Co-Authored-By: Joannah Nanjekye <joannah.nanjekye@ibm.com>
diff --git a/Lib/test/libregrtest/main.py b/Lib/test/libregrtest/main.py
index 87278d0..3cfbb40 100644
--- a/Lib/test/libregrtest/main.py
+++ b/Lib/test/libregrtest/main.py
@@ -14,7 +14,7 @@
 from test.libregrtest.runtest import (
     findtests, runtest, get_abs_module,
     STDTESTS, NOTTESTS, PASSED, FAILED, ENV_CHANGED, SKIPPED, RESOURCE_DENIED,
-    INTERRUPTED, CHILD_ERROR, TEST_DID_NOT_RUN,
+    INTERRUPTED, CHILD_ERROR, TEST_DID_NOT_RUN, TIMEOUT,
     PROGRESS_MIN_TIME, format_test_result, is_failed)
 from test.libregrtest.setup import setup_tests
 from test.libregrtest.pgo import setup_pgo_tests
@@ -115,6 +115,8 @@
             self.run_no_tests.append(test_name)
         elif ok == INTERRUPTED:
             self.interrupted = True
+        elif ok == TIMEOUT:
+            self.bad.append(test_name)
         else:
             raise ValueError("invalid test result: %r" % ok)