feature #16125 Replace is_callable checks with type hints (mpajunen, nicolas-grekas)

This PR was merged into the 3.0-dev branch.

Discussion
----------

Replace is_callable checks with type hints

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |  #14330
| License       | MIT
| Doc PR        | -

Also removes tests checking the exceptions thrown from
the removed is_callable checks.

Commits
-------

7685cdd Add more callable type hints
4e0c6e1 Replace is_callable checks with type hints

Author: fabpot

Normalizer/AbstractNormalizer.php

@@ -86,15 +86,9 @@ public function setCircularReferenceLimit($circularReferenceLimit)
      * @param callable $circularReferenceHandler
      *
      * @return self
-     *
-     * @throws InvalidArgumentException
      */
-    public function setCircularReferenceHandler($circularReferenceHandler)
+    public function setCircularReferenceHandler(callable $circularReferenceHandler)
     {
-        if (!is_callable($circularReferenceHandler)) {
-            throw new InvalidArgumentException('The given circular reference handler is not callable.');
-        }
-
         $this->circularReferenceHandler = $circularReferenceHandler;
 
         return $this;
@@ -103,7 +97,7 @@ public function setCircularReferenceHandler($circularReferenceHandler)
     /**
      * Set normalization callbacks.
      *
-     * @param array $callbacks help normalize the result
+     * @param callable[] $callbacks help normalize the result
      *
      * @return self
      *