remove deprecated static callables from tests

Author: jonas.kraska

tests/GenericMapTest.php

@@ -1105,7 +1105,6 @@ public function testWillJoinValuesWithSeperator(): void
     public function testWillExchangeKeys(array $initial, callable $keyGenerator, array $expected): void
     {
         $map = new GenericMap($initial);
-        /** @psalm-suppress PossiblyInvalidArgument Might be a psalm bug */
         $exchanged = $map->keyExchange($keyGenerator);
         self::assertEquals($expected, $exchanged->toNativeArray());
     }

tests/GenericOrderedListTest.php

@@ -479,7 +479,7 @@ public function testCanConvertToMap(): void
             $object2,
         ]);
 
-        $mapped = $list->toMap(static function (GenericObject $object): string {
+        $mapped = $list->toMap(function (GenericObject $object): string {
             $hash = spl_object_hash($object);
             Assert::stringNotEmpty($hash);
 
@@ -719,7 +719,7 @@ public function testToMapConversionErrorsOnIntegerishKeys(): void
     {
         $this->expectException(InvalidArgumentException::class);
         $list = new GenericOrderedList([1, 2, 3]);
-        $list->toMap(static function (int $value): string {
+        $list->toMap(function (int $value): string {
             return (string) $value;
         });
     }