Prepare tests for upcoming twisted version

Twisted recently changed behavior of logger on failures [1]. It newly
logs the `Main loop terminated.` even on exceptions, which breaks two
test in twistedsupport test suite. This hack attempts to address the
upcoming issue.

[1] twisted/twisted#12207

testtools/tests/twistedsupport/test_runtest.py

@@ -16,7 +16,6 @@
  Contains,
  ContainsAll,
  ContainsDict,
- EndsWith,
  Equals,
  Is,
  KeysEqual,
@@ -749,7 +748,7 @@ def test_something(self):
  test,
  {
  "traceback": Not(Is(None)),
- "twisted-log": AsText(EndsWith(" foo\n")),
+ "twisted-log": AsText(Contains(" foo\n")),
  },
  ),
  ("stopTest", test),
@@ -790,7 +789,7 @@ def test_something(self):
  result = self.make_result()
  runner.run(result)
  self.assertThat(
- messages, MatchesListwise([ContainsDict({"message": Equals(("foo",))})])
+ messages[0:1], MatchesListwise([ContainsDict({"message": Equals(("foo",))})])
  )
 
  def test_restore_observers(self):