Merge branch '6.4' into 7.0

* 6.4:
  [Serializer] Improve exception message in UnwrappingDenormalizer
  [PropertyInfo] Update DoctrineExtractor for new DBAL 4 BIGINT type
  Update security.nl.xlf
  [Validator] IBAN Check digits should always between 2 and 98
  [Security] Populate translations for trans-unit 20
  add missing plural translation messages
  filter out empty HTTP header parts
  [String] Fix folded in compat mode
  Remove calls to `getMockForAbstractClass()`
  [ErrorHandler] Do not call xdebug_get_function_stack() with xdebug >= 3.0 when not in develop mode
  [Serializer] Fix type for missing property
  add test for JSON response with null as content
  [Filesystem] Fix dumpFile `stat failed` error hitting custom handler
  Return false in isTtySupported() when open_basedir restrictions prevent access to /dev/tty.
  Remove calls to `TestCase::iniSet()` and calls to deprecated methods of `MockBuilder`
  [PhpUnitBridge] Fix `DeprecationErrorHandler` with PhpUnit 10

Author: fabpot

Tests/Transport/Smtp/SmtpTransportTest.php

@@ -194,7 +194,7 @@ public function testAssertResponseCodeWithNotValidCode()
 
     private function invokeAssertResponseCode(string $response, array $codes): void
     {
-        $transport = new SmtpTransport($this->getMockForAbstractClass(AbstractStream::class));
+        $transport = new SmtpTransport($this->createStub(AbstractStream::class));
         $m = new \ReflectionMethod($transport, 'assertResponseCode');
         $m->invoke($transport, $response, $codes);
     }