[ticket/12747] Drop support for Firebird

PHPBB3-12747

tests/RUNNING_TESTS.md

@@ -32,7 +32,6 @@ will be skipped:
 
 - apc (APC cache driver)
 - bz2 (compress tests)
-- interbase, pdo_firebird (Firebird database driver)
 - mysql, pdo_mysql (MySQL database driver)
 - mysqli, pdo_mysql (MySQLi database driver)
 - pcntl (flock class)
@@ -82,16 +81,10 @@ Special Database Cases
 ----------------------
 In order to run tests on some of the databases that we support, it will be
 necessary to provide a custom DSN string in test_config.php. This is only
-needed for MSSQL 2000+ (PHP module), MSSQL via ODBC, and Firebird when
-PDO_Firebird does not work on your system
-(https://bugs.php.net/bug.php?id=61183). The variable must be named `$custom_dsn`.
+needed for MSSQL 2000+ (PHP module) and MSSQL via ODBC. The variable must be
+named `$custom_dsn`.
 
-Examples:
-Firebird using http://www.firebirdsql.org/en/odbc-driver/
-
-    $custom_dsn = "Driver={Firebird/InterBase(r) driver};dbname=$dbhost:$dbname";
-
-MSSQL
+Example MSSQL:
 
     $custom_dsn = "Driver={SQL Server Native Client 10.0};Server=$dbhost;Database=$dbname";