Author: fe2s <aka.fe2s@gmail.com>
Author: Oleksiy Dyagilev <oleksiy_dyagilev@epam.com>

Closes #6956 from fe2s/fix-run-tests and squashes the following commits:

31b6edc [fe2s] str is a built-in function, so using it as a variable name will lead to spurious warnings in some Python linters
7d781a0 [fe2s] fixing for openjdk/IBM, seems like they have slightly different wording, but all have 'version' word. Surrounding with spaces for the case if version word appears in _JAVA_OPTIONS
cd455ef [fe2s] address comment, looking for java version string rather than expecting to have on a certain line number
ad577d7 [Oleksiy Dyagilev] [SPARK-8558][BUILD] Script /dev/run-tests fails when _JAVA_OPTIONS env var set