Missing support for redirect tests

[Johannes Schlüter]

run-tests.php has a feature for "redirect tests" which is used to test "common" PDO test cases with different drivers. The implementation of the redirect feature assumes that the working directory when running the tests is the root of a PHP source tree which we can't guarantee.

We might add a magic to find it and set the cwd correctly (magic is needed for situations where one selects pdo_mysql tests for instance..) or add an additional field to the starting wizard - or fix the redirect feature.

Step 2 would be to make sure the .exp and .out files are found (they will be placed in the directory from which the redirect was started (ext/pdo_mysql/tests/ for isntance) not where the phpt file is (ext/pdo/tests))