Adjust multi-actor debugger test

It turns out recent improvements have made the debugger too good
so we need to just terminate the continue loop in this test when
we finally see the "spawn error" crash out because the breakpoint
forever case will literally, continue forever XD

tests/test_debugger.py

@@ -279,8 +279,10 @@ def test_multi_subactors(spawn):
     assert "Attaching pdb to actor: ('breakpoint_forever'" in before
 
     # wait for spawn error to show up
-    while 'breakpoint_forever' in before:
+    spawn_err = "Attaching to pdb in crashed actor: ('spawn_error'"
+    while spawn_err not in before:
         child.sendline('c')
+        time.sleep(0.1)
         child.expect(r"\(Pdb\+\+\)")
         before = str(child.before.decode())
 
@@ -288,7 +290,7 @@ def test_multi_subactors(spawn):
     # child.sendline('c')
     # child.expect(r"\(Pdb\+\+\)")
     # before = str(child.before.decode())
-    assert "Attaching to pdb in crashed actor: ('spawn_error'" in before
+    assert spawn_err in before
     assert "RemoteActorError: ('name_error_1'" in before
 
     # now run some "continues" to show re-entries