Improve test coverage for the ArbitraryParenthesesSpacing sniff

This commit improves the test coverage for the ArbitraryParenthesesSpacing
sniff by adding one more test case files to exercise a part of the
sniff code that checks for invalid syntax.

Author: rodrigoprimo

src/Standards/Generic/Tests/WhiteSpace/ArbitraryParenthesesSpacingUnitTest.2.inc

@@ -0,0 +1,4 @@
+<?php
+
+// Intentional parse error. Testing that the sniff is *not* triggered in this case.
+function something $param ) {}