Added regression test for #1351.
Fix #1351: Isolated TestResult contains serialized test class upon failure.
Fixed PDOException::getCode() string vs. int mismatch.
Fixed bogus expectation in ExceptionStackTest.

Catching a PHPUnit exception and rethrowing it as a non-PHPUnit exception does not make any sense.
Merge pull request #1352 from sun/result-isolation

Remove instantiated (child process) objects from TestFailure