Dropping the tests/functional directory

[bantu]

I am not seeing how functional tests (which cover multiple units) [...]

This is sufficient reason to withdraw this RFC.

[naderman]

For the record the original reason was that functional tests would cause parse errors on PHP <= 5.3 I believe, and at the time we still ran other tests on PHP 5.2. The PHPUnit group filter still includes all test files so that was not sufficient to prevent parse errors.

Moving this to rejected anyway.