Load dead-code-detector in self-analysis only on PHP 8.2 and later

On PHP 8.1 serialize() does not trim its buffer, so every cache key that
DeadCodeRule builds with it holds a 4 KB allocation. The rule then needs
about 150 MB more in the main process, and the Windows PHP 8.1 job runs
out of its memory limit.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: 2 people

build/ignore-by-php-version.neon.php

@@ -6,13 +6,16 @@
 } else {
 	$includes[] = __DIR__ . '/baseline-pre-8.0.neon';
 }
-if (PHP_VERSION_ID >= 80100) {
-	$includes[] = __DIR__ . '/../vendor/shipmonk/dead-code-detector/rules.neon';
-} else {
+if (PHP_VERSION_ID < 80100) {
 	$includes[] = __DIR__ . '/enums.neon';
 	$includes[] = __DIR__ . '/readonly-property.neon';
 }
 
+// PHP 8.1's serialize() does not trim its buffer, so the rule's cache keys cost 4 KB each
+if (PHP_VERSION_ID >= 80200) {
+	$includes[] = __DIR__ . '/../vendor/shipmonk/dead-code-detector/rules.neon';
+}
+
 if (PHP_VERSION_ID >= 70400) {
 	$includes[] = __DIR__ . '/ignore-gte-php7.4-errors.neon';
 }