only sort when necessary and faster hash

* sort is much more expensive than count, so we only sort if we have something to sort
* could implement for ksort too, but advantage there is minimal since we almost always have more than 1 possibility
* use same hash algorithm as in other places (= faster)
* reduces runtime by 2-3%

src/Psalm/Internal/Clause.php

@@ -10,15 +10,17 @@
 use function array_unique;
 use function array_values;
 use function count;
+use function hash;
 use function implode;
 use function ksort;
-use function md5;
 use function reset;
 use function serialize;
 use function sort;
 use function strpos;
 use function substr;
 
+use const PHP_VERSION_ID;
+
 /**
  * @internal
  *
@@ -106,11 +108,15 @@ public function __construct(
         } else {
             ksort($possibilities);
 
-            foreach ($possibilities as $i => $_) {
+            foreach ($possibilities as $i => $v) {
+                if (count($v) < 2) {
+                    continue;
+                }
                 sort($possibilities[$i]);
             }
 
-            $this->hash = md5(serialize($possibilities));
+            $data = serialize($possibilities);
+            $this->hash = PHP_VERSION_ID >= 80100 ? hash('xxh128', $data) : hash('md4', $data);
         }
     }