Fix test definition of igetattr recursion and context_manager_inference

Ref pylint-dev#663. This test did not actually check for regression of the issue
fixed in 55076ca (i.e. it also passed on c87bea1 before the fix was
applied). Additionally, it over-specified the behaviour it was
attempting to check: whether the value returned from the context manager
was Uninferable was not directly relevant to the test, so when this
value changed due to unrelated fixes in inference, this test failed.

tests/unittest_inference.py

@@ -5312,26 +5312,20 @@ class Cls:
 def test_prevent_recursion_error_in_igetattr_and_context_manager_inference():
  code = """
  class DummyContext(object):
- def method(self, msg): # pylint: disable=C0103
- pass
  def __enter__(self):
- pass
+ return self
  def __exit__(self, ex_type, ex_value, ex_tb):
  return True
 
- class CallMeMaybe(object):
- def __call__(self):
- while False:
- with DummyContext() as con:
- f_method = con.method
- break
+ if False:
+ with DummyContext() as con:
+ pass
 
- with DummyContext() as con:
- con #@
- f_method = con.method
+ with DummyContext() as con:
+ con.__enter__ #@
  """
  node = extract_node(code)
- assert next(node.infer()) is util.Uninferable
+ next(node.infer())  # should not raise StopIteration/RuntimeError
 
 
 def test_infer_context_manager_with_unknown_args():