[BUGFIX] PHP 5.4 unit test warnings

PHP 5.4 throws warnings "Creating default object from empty value"
warnings if $foo->bar is accessed and $foo is not an object. The patch
fixes ConditionMatcherTest in this regard and does some other minor
cleanups within the test class.

Fixes: #42622
Releases: 6.0

Change-Id: I9d04618d88127b07d460be8dbd81c64633991bd6
Reviewed-on: http://review.typo3.org/16124
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn