Add a simple test for these issues

test/tests/signal_ref_test.py

+import os
+import signal
+import threading
+import time
+
+def f():
+    time.sleep(0.1)
+    os.kill(os.getpid(), signal.SIGINT)
+t = threading.Thread(target=f)
+t.start()
+
+def g():
+    while True:
+        -(0.2 ** 5)
+try:
+    g()
+    assert 0
+except KeyboardInterrupt:
+    pass