Merge branch '4.3' into 4.4

* 4.3:
  [Form] fix return type on FormDataCollector
  [Cache][DI] cleanup

Author: nicolas-grekas

Tests/Compiler/ResolveBindingsPassTest.php

@@ -12,7 +12,6 @@
 namespace Symfony\Component\DependencyInjection\Tests\Compiler;
 
 use PHPUnit\Framework\TestCase;
-use PHPUnit\Framework\Warning;
 use Symfony\Component\DependencyInjection\Argument\BoundArgument;
 use Symfony\Component\DependencyInjection\Compiler\AutowireRequiredMethodsPass;
 use Symfony\Component\DependencyInjection\Compiler\ResolveBindingsPass;