[1.6] Fix path whitespace edge case in tests

[divinity76]

if the file has a space in the path, the command would not account for that and generate an invalid invocation. for example if the path was /home/hans henrik/wrench/tests/Test/ServerTestHelper.php the command would previously fail.

[GrahamCampbell]

Thanks for the PR. I'm not sure that will work properly on Windows, however.

[divinity76]

@GrahamCampbell it's the correct approach on Windows as well (but escapeshellarg() is not foolproof on Windows ), but it doesn't really matter in this specific file, tests/Test/ServerTestHelper.php needs a major overhaul to work on Windows, it currently contains stuff like

                \exec('ps -ao pid,ppid | col | tail -n +2 | grep \' '
(...)
            $this->getCommand(),
            [
                0 => ['file', '/dev/null', 'r'],
 (...)
 /usr/bin/env

[GrahamCampbell]

Great, thanks for being on top of this.