Minor cleanup from rails#46097

1) We don't need this comment
2) The begin/end was redudant and not necessary

Author: eileencodes

activerecord/lib/active_record/migration.rb

@@ -657,7 +657,6 @@ def load_schema_if_pending!
         # Establish a new connection, the old database may be gone (db:test:prepare uses purge)
         Base.establish_connection(current_db_config)
 
-        # Ensure all migrations have succeeded
         check_pending_migrations(db_configs: all_configs)
       end
 

activerecord/test/cases/migration/pending_migrations_test.rb

@@ -114,10 +114,9 @@ def test_with_multiple_database
             CheckPending.new(@app).call({})
           end
 
-          begin
-            ActiveRecord::Base.establish_connection(:secondary)
-            quietly { run_migrations }
-          end
+          ActiveRecord::Base.establish_connection(:secondary)
+          quietly { run_migrations }
+
           ActiveRecord::Base.establish_connection(:primary)
 
           @app.expect :call, nil, [{}]