Use str_starts_with instead of regex logic

Author: alcaeus

tests/UnifiedSpecTests/UnifiedSpecTest.php

@@ -14,8 +14,7 @@
 use function basename;
 use function dirname;
 use function glob;
-use function preg_match;
-use function sprintf;
+use function str_starts_with;
 
 /**
  * Unified test format spec tests.
@@ -101,7 +100,7 @@ public function setUp(): void
         }
 
         foreach (self::$incompleteTestGroups as $testGroup => $reason) {
-            if (preg_match(sprintf('#^%s#', $testGroup), $this->dataDescription())) {
+            if (str_starts_with($this->dataDescription(), $testGroup)) {
                 $this->markTestIncomplete($reason);
             }
         }