Skip a recursion depth check test when running under CPython and have a trace function set. Otherwise a Python fatal error about hitting an unrecoverable recursion depth gets triggered.
Skip a recursion depth check test when running under CPython and have a trace
function set. Otherwise a Python fatal error about hitting an unrecoverable
recursion depth gets triggered.

Closes issue #10985. Code review by Georg Brandl.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator