Fix flaky test by freezing time before increment operation (#57905)

This prevents timing race conditions where time can advance between
when the cache value is incremented (which records a timestamp) and
when subsequent time-based checks occur, causing intermittent test failures.

Author: sumaiazaman

tests/Cache/CacheArrayStoreTest.php

@@ -117,6 +117,8 @@ public function testIncrementNonNumericValues()
 
     public function testNonExistingKeysCanBeIncremented()
     {
+        Carbon::setTestNow(Carbon::now());
+
         $store = new ArrayStore;
         $result = $store->increment('foo');
         $this->assertEquals(1, $result);