Merge branch '3.4' into 4.4

* 3.4:
  [Filesystem] Handle paths on different drives
  [WebProfiler] Do not add src-elem CSP directives if they do not exist
  [Yaml] fix parse error when unindented collections contain a comment
  [3.4][Inflector] Improve testSingularize() argument name
  [PhpUnitBridge] fix PHP 5.3 compat again
  Skip validation when email is an empty object
  fix sr_Latn translation
  [Validator] fix lazy property usage.
  Fix annotation
  [PhpUnitBridge] fix compat with PHP 5.3
  [DX] Show the ParseException message in YAML file loaders

Author: nicolas-grekas

Form.php

@@ -959,7 +959,7 @@ public function offsetExists($name)
      *
      * @return FormInterface The child form
      *
-     * @throws \OutOfBoundsException if the named child does not exist
+     * @throws OutOfBoundsException if the named child does not exist
      */
     public function offsetGet($name)
     {

FormInterface.php

@@ -62,7 +62,7 @@ public function add($child, $type = null, array $options = []);
      *
      * @return self
      *
-     * @throws \OutOfBoundsException if the named child does not exist
+     * @throws Exception\OutOfBoundsException if the named child does not exist
      */
     public function get($name);