AbstractArrayDeclarationSniff::getActualArrayKey(): minor simplification

The tokenization of fully qualified `true`/`false`/`null` has been changed for both PHPCS 3.x (as of 3.13.3) as well as PHPCS 4.0.

The new tokenization means we don't need to take these tokens being tokenized as `T_STRING` or `T_NAME_FULLY_QUALIFIED` into account anymore, as long as the minimum supported PHPCS version will be PHPCS 3.13.3 (which it will be since the merge of PR 698).

This commit removes the code which has now become redundant.

Ref:
* PHPCSStandards/PHP_CodeSniffer 1201
* PHPCSStandards/PHP_CodeSniffer 1206

Author: jrfnl

PHPCSUtils/AbstractSniffs/AbstractArrayDeclarationSniff.php

@@ -478,31 +478,15 @@ public function getActualArrayKey(File $phpcsFile, $startPtr, $endPtr)
                 continue;
             }
 
-            // Handle FQN true/false/null.
-            if ($this->tokens[$i]['code'] === \T_NAME_FULLY_QUALIFIED) {
-                $compareReadyKeyword = \strtolower($this->tokens[$i]['content']);
-                if ($compareReadyKeyword === '\true'
-                    || $compareReadyKeyword === '\false'
-                    || $compareReadyKeyword === '\null'
-                ) {
-                    // FQN true/false/null on PHPCS 4.x. This can be handled.
-                    $content .= $this->tokens[$i]['content'];
-                    continue;
-                }
-            } elseif ($this->tokens[$i]['code'] === \T_NS_SEPARATOR) {
-                // PHPCS 3.x.
+            // Handle FQN true/false/null for PHPCS 3.x.
+            if ($this->tokens[$i]['code'] === \T_NS_SEPARATOR) {
                 $nextNonEmpty   = $phpcsFile->findNext(Tokens::$emptyTokens, ($i + 1), null, true);
                 $nextNonEmptyLC = \strtolower($this->tokens[$nextNonEmpty]['content']);
                 if ($nextNonEmpty !== false
-                    // PHPCS 3.x with PHP < 8.0.
                     && ($this->tokens[$nextNonEmpty]['code'] === \T_TRUE
                     || $this->tokens[$nextNonEmpty]['code'] === \T_FALSE
-                    || $this->tokens[$nextNonEmpty]['code'] === \T_NULL
-                    // PHPCS 3.x with PHP >= 8.0 where the namespaced name tokenization has been undone.
-                    || ($this->tokens[$nextNonEmpty]['code'] === \T_STRING
-                        && ($nextNonEmptyLC === 'true' || $nextNonEmptyLC === 'false' || $nextNonEmptyLC === 'null')))
+                    || $this->tokens[$nextNonEmpty]['code'] === \T_NULL)
                 ) {
-                    // FQN true/false/null on PHPCS 3.x. This can be handled.
                     $content .= $this->tokens[$nextNonEmpty]['content'];
                     $i        = $nextNonEmpty;
                     continue;