Redirect STDERR to STDOUT when running PHPT tests

This is the current behaviour of the "run-tests.php" script which runs
all entire PHP source test suite.
Create methods to handle sections in PHPT test case
Define PHPUnit_Util_PHP instance on PhptTestCase
Create tests for PHPT execution
Implement CLEAN section for PHPT test cases
Implement EXPECTREGEX section for PHPT test cases