Merge branch '4.0'

* 4.0:
  [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
  isCsrfTokenValid() replace string  by ?string
  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

Finder.php

@@ -313,6 +313,8 @@ public function exclude($dirs)
     /**
      * Excludes "hidden" directories and files (starting with a dot).
      *
+     * This option is enabled by default.
+     *
      * @param bool $ignoreDotFiles Whether to exclude "hidden" files or not
      *
      * @return $this
@@ -333,6 +335,8 @@ public function ignoreDotFiles($ignoreDotFiles)
     /**
      * Forces the finder to ignore version control directories.
      *
+     * This option is enabled by default.
+     *
      * @param bool $ignoreVCS Whether to exclude VCS files or not
      *
      * @return $this