Merge branch '5.4' into 6.2

* 5.4:
  [Translation][Mailer] Convert `$this` calls to static ones in data providers
  [BC Break] Make data providers for abstract test cases static
  use TestCase suffix for abstract tests in Tests directories
  Fix Request locale property doc types
  Bump absolute lowest dep to 4.4

Author: nicolas-grekas

Tests/MessageMediaTransportFactoryTest.php

@@ -21,7 +21,7 @@ public function createFactory(): MessageMediaTransportFactory
         return new MessageMediaTransportFactory();
     }
 
-    public function createProvider(): iterable
+    public static function createProvider(): iterable
     {
         yield [
             'messagemedia://host.test',
@@ -34,13 +34,13 @@ public function createProvider(): iterable
         ];
     }
 
-    public function supportsProvider(): iterable
+    public static function supportsProvider(): iterable
     {
         yield [true, 'messagemedia://apiKey:apiSecret@default'];
         yield [false, 'somethingElse://apiKey:apiSecret@default'];
     }
 
-    public function unsupportedSchemeProvider(): iterable
+    public static function unsupportedSchemeProvider(): iterable
     {
         yield ['somethingElse://apiKey:apiSecret@default'];
     }

Tests/MessageMediaTransportTest.php

@@ -68,7 +68,7 @@ public function testExceptionIsThrownWhenHttpSendFailed(int $statusCode, string
         $transport->send(new SmsMessage('+61491570156', 'Hello!'));
     }
 
-    public function exceptionIsThrownWhenHttpSendFailedProvider(): iterable
+    public static function exceptionIsThrownWhenHttpSendFailedProvider(): iterable
     {
         yield [503, '', 'Unable to send the SMS: "Unknown reason".'];
         yield [500, '{"details": ["Something went wrong."]}', 'Unable to send the SMS: "Something went wrong.".'];