Fix output in tests

PR #47191 added tests that create tables, but didn't turn off verbose
mode, so running tests caused unintended output. Sets verbose to false
for both tests.

activerecord/test/cases/serialized_attribute_test.rb

@@ -406,6 +406,9 @@ def test_values_cast_from_nil_are_persisted_as_nil
   # MySQL doesn't support default values for text columns, so we need to skip this test for MySQL
   if !current_adapter?(:Mysql2Adapter)
     def test_serialized_attribute_with_default_can_update_to_default
+      @verbose_was = ActiveRecord::Migration.verbose
+      ActiveRecord::Migration.verbose = false
+
       ActiveRecord::Schema.define do
         create_table :tmp_posts, force: true do |t|
           t.text     :content, null: false, default: "{}"
@@ -421,9 +424,14 @@ def test_serialized_attribute_with_default_can_update_to_default
 
       t.update!(content: {})
       assert_equal({}, t.content)
+    ensure
+      ActiveRecord::Migration.verbose = @verbose_was
     end
 
     def test_nil_is_always_persisted_as_default
+      @verbose_was = ActiveRecord::Migration.verbose
+      ActiveRecord::Migration.verbose = false
+
       ActiveRecord::Schema.define do
         create_table :tmp_posts, force: true do |t|
           t.text     :content, null: false, default: "{}"
@@ -437,6 +445,8 @@ def test_nil_is_always_persisted_as_default
       t = klass.create!(content: { foo: "bar" })
       t.update_attribute :content, nil
       assert_equal({}, t.content)
+    ensure
+      ActiveRecord::Migration.verbose = @verbose_was
     end
   end