Removed invalid assert in testatomic

(cherry picked from commit 8adab0b88a)

test/testatomic.c

@@ -234,7 +234,8 @@ static void RunEpicTest()
     v = SDL_AtomicGet(&good);
     SDL_Log("Atomic %d Non-Atomic %d\n", v, bad);
     SDL_assert(v == Expect);
-    SDL_assert(bad != Expect);
+    /* We can't guarantee that bad != Expect, this would happen on a single core system, for example. */
+    /*SDL_assert(bad != Expect);*/
 }
 
 /* End atomic operation test */