Disable hypothesis tests on 3.8

These are taking orders of magnitude longer, and I verified
that they do pass with smaller example counts.  I'd rather disable
this for 3.8 than to lower the num examples across all python versions.

Author: jamesls

.travis.yml

@@ -25,6 +25,6 @@ install:
   - pip install dist/*.whl
 script:
   - cd tests/ && nosetests --with-coverage --cover-package jmespath .
-  - if [[ $TRAVIS_PYTHON_VERSION != '2.6' ]]; then JP_MAX_EXAMPLES=10000 nosetests ../extra/test_hypothesis.py; fi
+  - if [[ $TRAVIS_PYTHON_VERSION != '2.6' ]] && [[ $TRAVIS_PYTHON_VERSION != '3.8' ]]; then JP_MAX_EXAMPLES=10000 nosetests ../extra/test_hypothesis.py; fi
 after_success:
   - codecov