Remove unused explicit delegation to `klass` in `relation`

It is only used `primary_key` and `connection` in the internal, so it is
not needed to delegate others to `klass` explicitly.
This doesn't change public behavior because `relation` will delegate
missing method to `klass`.

activerecord/lib/active_record/relation.rb

@@ -580,7 +580,7 @@ def to_sql
     #
     #   User.where(name: 'Oscar').where_values_hash
     #   # => {name: "Oscar"}
-    def where_values_hash(relation_table_name = table_name)
+    def where_values_hash(relation_table_name = klass.table_name)
       where_clause.to_h(relation_table_name)
     end
 

activerecord/lib/active_record/relation/delegation.rb

@@ -43,8 +43,7 @@ def inherited(child_class)
              :to_sentence, :to_formatted_s, :as_json,
              :shuffle, :split, :slice, :index, :rindex, to: :records
 
-    delegate :table_name, :quoted_table_name, :primary_key, :quoted_primary_key,
-             :connection, :columns_hash, to: :klass
+    delegate :primary_key, :connection, to: :klass
 
     module ClassSpecificRelation # :nodoc:
       extend ActiveSupport::Concern

activerecord/test/cases/relation_test.rb

@@ -73,11 +73,6 @@ def test_tree_is_not_traversed
       assert_equal({}, relation.where_values_hash)
     end
 
-    def test_table_name_delegates_to_klass
-      relation = Relation.new(FakeKlass, :b, Post.predicate_builder)
-      assert_equal "posts", relation.table_name
-    end
-
     def test_scope_for_create
       relation = Relation.new(FakeKlass, :b, nil)
       assert_equal({}, relation.scope_for_create)