message: Skip TestNoreturnUnwind on linux+clang+arm
  I was over-eager to unable this test in r304976. It still fails in this
  combination, at there does not seem to be anything we can do about it,
  as the generated code does not preserve the link register.
diff: @@ -17,6 +17,8 @@ class NoreturnUnwind(TestBase):
  mydir = TestBase.compute_mydir(__file__)
  @skipIfWindows # clang-cl does not support gcc style attributes.
  + # clang does not preserve LR in noreturn functions, making unwinding impossible
  + @skipIf(compiler="clang", archs=['arm'], oslist=['linux'])
  def test(self):
  """Test that we can backtrace correctly with 'noreturn' functions on the stack"""
  self.build()
  