fix style failures in webkitpy: expected 2 blank lines found 1

fix style failures in webkitpy: expected 2 blank lines found 1
https://bugs.webkit.org/show_bug.cgi?id=179529

Reviewed by Alex Christensen.

* Scripts/webkitpy/benchmark_runner/run_benchmark.py: Added a blank line to follow style guidelines.
* Scripts/webkitpy/benchmark_runner/browser_driver/osx_chrome_driver.py: Ditto.
* Scripts/webkitpy/common/system/platforminfo_mock.py: Ditto.
* Scripts/webkitpy/common/version.py: Ditto.
* Scripts/webkitpy/layout_tests/models/test_failures.py: Ditto.
* Scripts/webkitpy/port/mac_unittest.py: Ditto.
* Scripts/webkitpy/port/simulator_process.py: Ditto.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@224688 268f45cc-cd09-0410-ab3c-d52691b4dbfc