Make the new test ext_dso_test pass, but only by making it less thorough.

Because the test passes, move it from the php5-only directory test/zend/bad/ext/ext_dso_test
to the better named/located directory test/slow/ext_dso_test

The test will be made more thorough once the underlying bugs in the ezc layer are fixed
in a subsequent commit.

These changes follow suggests from Fred Emmott.