Merge branch '3.4' into 4.0

* 3.4:
  [YAML] Issue #26065: leading spaces in YAML multi-line string literals
  [Bridge\PhpUnit] Exit as late as possible
  [Bridge\PhpUnit] Cleanup BC layer
  [PhpBridge] add PHPUnit 7 support to SymfonyTestsListener
  [Lock] Log already-locked errors as "notice" instead of "warning"
  add context to serialize and deserialize
  Update Repository Symlink Helper
  Document explicitly that dotfiles and vcs files are ignored by default
  [HttpKernel] don't try to wire Request argument with controller.service_arguments
  Make kernel build time optionally deterministic
  Use 0 for unlimited expiry
  [Routing] fix typo
  Bump default PHPUnit version from 6.3 to 6.5
  do not mock the container builder in tests
  [Cache][WebProfiler] fix collecting cache stats with sub-requests + allow clearing calls

Author: nicolas-grekas

Tests/Fixtures/dumper/url_matcher4.php

@@ -62,7 +62,7 @@ public function match($rawPathinfo)
         not_get_and_head:
 
         // post_and_head
-        if ('/post_and_get' === $pathinfo) {
+        if ('/post_and_head' === $pathinfo) {
             if (!in_array($requestMethod, array('POST', 'HEAD'))) {
                 $allow = array_merge($allow, array('POST', 'HEAD'));
                 goto not_post_and_head;

Tests/Matcher/Dumper/PhpMatcherDumperTest.php

@@ -354,7 +354,7 @@ public function getRouteCollections()
             array('GET', 'HEAD')
         ));
         $headMatchCasesCollection->add('post_and_head', new Route(
-            '/post_and_get',
+            '/post_and_head',
             array(),
             array(),
             array(),