Most oci8 tests fail out-of-the-box because a typical host won't have
an Oracle database instance available. Other database drivers like
mysqli and pgsql address this problem with an include file, inserted
into SKIPIF, that skips the test if no connection at all can be made.
This commits adds such a file (skipifconnectfailure.inc) for oci8, and
adds the corresponding SKIPIF to any tests that connect to a database.
Closes GH-11804
* ext/oci8/tests/lob_aliases.phpt: drop unnecessary SKIPIF.
Kamil Tekiela