Assume that getmypid() never returns false

my background research on this informs me that this returns false on negative PID, which never happens because the underlying C API call never fails - not on linux, bsd, or windows.

src/pocketmine/network/mcpe/protocol/types/RuntimeBlockMapping.php

@@ -123,7 +123,7 @@ final class RuntimeBlockMapping{
 	 */
 	private static function randomizeTable(array $table) : array{
 		$postSeed = mt_rand(); //save a seed to set afterwards, to avoid poor quality randoms
-		mt_srand(getmypid() ?: 0); //Use a seed which is the same on all threads. This isn't a secure seed, but we don't care.
+		mt_srand(getmypid()); //Use a seed which is the same on all threads. This isn't a secure seed, but we don't care.
 		shuffle($table);
 		mt_srand($postSeed); //restore a good quality seed that isn't dependent on PID
 		return $table;