Tokenizer/PHP: minor bugfix for match tokenization

Oops.. still missed that one, even though I'd run the tests on various PHP versions locally so many times.... luckily CI caught it anyhow with one of the sniffs.

Author: jrfnl

src/Tokenizers/PHP.php

@@ -1290,7 +1290,9 @@ protected function tokenize($string)
 
                     // Next was an open parenthesis, now check what is before the match keyword.
                     for ($y = ($stackPtr - 1); $y >= 0; $y--) {
-                        if (isset(Util\Tokens::$emptyTokens[$tokens[$y][0]]) === true) {
+                        if (is_array($tokens[$y]) === true
+                            && isset(Util\Tokens::$emptyTokens[$tokens[$y][0]]) === true
+                        ) {
                             continue;
                         }