test(Database): fix state leaks and random-order test determinism for MySQLi, PostgreSQL, and OCI8

[gr8man]

Fixes database tests to be deterministic under random execution order
for MySQLi, PostgreSQL, and OCI8 drivers.
Ref: #9968

MySQLi (commits cd8f5dc, 8cc20d3)

• ConnectTest: use correct host/port for connection assertions.
• ForgeTest: access addField before usage in testDropTableSuccess.
• WorkerModeTest: clear history between runs.
• FoundRowsTest, NumberNativeTest: remove setPrefix() calls that leaked
  prefix state to subsequent tests.

PostgreSQL (commit 24d5a44)

• ForgeTest::testDropTableSuccess: verify table existence with correct
  table name after creation.
• ConnectTest: skip charset assertion when not applicable.

OCI8 (commit fc9e325)

• Connection::initialize() – sets NLS_DATE_FORMAT, NLS_TIMESTAMP_FORMAT,
  and NLS_TIMESTAMP_TZ_FORMAT via ALTER SESSION after connecting.
  Prevents ORA-01843 "invalid month" when NLS env vars are not set.
• _indexData() – wraps $row->CONSTRAINT_TYPE ?? '' to avoid PHP 8.1+
  deprecation "Using null as an array offset" for indexes without a
  matching constraint.
• MetadataTest – captures prefix before createExtraneousTable() so the
  original prefix is preserved even if an exception is thrown.
• ExecuteLogMessageFormatTest – removes stale OCI8-specific array_slice
  that caused a backtrace line pattern mismatch.

All 859 OCI8 database tests pass with 0 failures in both default and
randomised execution order. MySQLi and PostgreSQL tests also pass
deterministically under random order.

[gr8man]

IMPORTANT

Note to reviewers and developers: Please ensure that tests are run regularly with the --order-by=random flag during development. Identifying test pollution and global state leakage bugs at a later stage is extremely difficult and time-consuming, as these failures only manifest under very specific test suite execution orders.