[PATCH V2] tests: make run-tests.py invokes tests with needed variables only (issue5069)

[Yuya Nishihara]

On Mon, 28 Mar 2016 13:52:31 +0200, liscju wrote:
> +def copyusedenviron(environ):
> +    return {key: environ[key] for key in usedenvvariables if key in environ}

Use dict(). The dict comprehension requires Python 2.7+.

https://www.python.org/dev/peps/pep-0274/