minor #17480 Static code analysis (Koc)

This PR was merged into the 2.3 branch.

Discussion
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Static code analysis

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

Things that done:
* fix case in method calls
* removed unused imports
* use shorter concat where it possible
* optimize some css
* removed duplicated array keys
* removed redurant return statements
* removed one-time variables
* do not pass arguments that not used in functions

Commits
-------

8db691a Static code analysis

Author: fabpot

Tests/XPath/TranslatorTest.php

@@ -74,7 +74,7 @@ public function testHtmlShakespear($css, $count)
         $document = simplexml_import_dom($document);
         $bodies = $document->xpath('//body');
         $elements = $bodies[0]->xpath($translator->cssToXPath($css));
-        $this->assertEquals($count, count($elements));
+        $this->assertCount($count, $elements);
     }
 
     public function getXpathLiteralTestData()