bug #41240 Fixed deprecation warnings about passing null as parameter (derrabus)

This PR was merged into the 4.4 branch.

Discussion
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Fixed deprecation warnings about passing null as parameter

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | N/A
| License       | MIT
| Doc PR        | N/A

Various built-in PHP functions will trigger a deprecation warning if `null` is passed as parameter. This PR attempts to fix all warnings that our test suite currently picks up.

Commits
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7d9bdf5734 Fixed deprecation warnings about passing null as parameter

Author: fabpot

Comparator/NumberComparator.php

@@ -41,8 +41,8 @@ class NumberComparator extends Comparator
      */
     public function __construct(?string $test)
     {
-        if (!preg_match('#^\s*(==|!=|[<>]=?)?\s*([0-9\.]+)\s*([kmg]i?)?\s*$#i', $test, $matches)) {
-            throw new \InvalidArgumentException(sprintf('Don\'t understand "%s" as a number test.', $test));
+        if (null === $test || !preg_match('#^\s*(==|!=|[<>]=?)?\s*([0-9\.]+)\s*([kmg]i?)?\s*$#i', $test, $matches)) {
+            throw new \InvalidArgumentException(sprintf('Don\'t understand "%s" as a number test.', $test ?? 'null'));
         }
 
         $target = $matches[2];