Fix the random failure of test_create_resets_cached_counters

- Tried specifying `id` for the `readers` records but it is
  interconnected with so many tests that many random tests started
  failing.
- So switched to the approach of deleting all readers in the
  `create_resets_cached_counters` test.

Author: prathamesh-sonpatki

activerecord/test/cases/associations/has_many_associations_test.rb

@@ -456,7 +456,10 @@ def test_finder_bang_method_with_dirty_target
   end
 
   def test_create_resets_cached_counters
+    Reader.delete_all
+
     person = Person.create!(first_name: "tenderlove")
+
     post   = Post.first
 
     assert_equal [], person.readers

activerecord/test/fixtures/readers.yml

@@ -1,9 +1,11 @@
 michael_welcome:
+  id: 1
   post_id: 1
-  person: michael
+  person_id: 1
   first_post_id: 2
 
 michael_authorless:
+  id: 2
   post_id: 3
-  person: michael
+  person_id: 1
   first_post_id: 3