minor #14121 CS: Pre incrementation/decrementation should be used if possible (gharlan)

This PR was merged into the 2.3 branch.

Discussion
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CS: Pre incrementation/decrementation should be used if possible

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

Fixes provided by new fixer: PHP-CS-Fixer/PHP-CS-Fixer#1113

If this pr is merged I would change the level of the fixer to `symfony`.

Commits
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c5123d6 CS: Pre incrementation/decrementation should be used if possible

Author: fabpot

Tests/Logger/DbalLoggerTest.php

@@ -121,7 +121,7 @@ public function testLogUTF8LongString()
 
         $shortString = '';
         $longString = '';
-        for ($i = 1; $i <= DbalLogger::MAX_STRING_LENGTH; $i++) {
+        for ($i = 1; $i <= DbalLogger::MAX_STRING_LENGTH; ++$i) {
             $shortString .= $testStringArray[$i % $testStringCount];
             $longString .= $testStringArray[$i % $testStringCount];
         }