Fix and re-enable tests/004.phpt

[Jon4t4n]

tests/004.phpt was disabled in PR #39. We want to fix this and re-enable the test.

Error:

Warning: main(): invalid statement handle  in .../tests/004.php on line 112

[MartinKoeditz]

Checked. ibase_free_result doesn't set pointer correct after freeing resource. Test passes after latest code release.
See https://github.com/FirebirdSQL/php-firebird/commit/7a0a740048133abd26debc0ffe5f1652aebfdfbc

Please check it too.

[Jon4t4n]

Hi, thanks for taking a look at this.

I haven't had time to dig into this, but the proposed fix makes the test pass with release builds. However, it causes failures with debug builds.

See this CI job (Commit 7a0a740):
https://github.com/FirebirdSQL/php-firebird/actions/runs/4056103722/jobs/6980149414