Assert the query result instead of checking for nothing raised

Nothing should be raised anyway 😄

Thanks @spastorino ❤
https://github.com/rails/rails/pull/8202/files#r2112067

activerecord/test/cases/finder_test.rb

@@ -611,10 +611,8 @@ def test_find_by_one_attribute_that_is_an_alias
   end
 
   def test_find_by_one_attribute_bang_with_blank_defined
-    BlankTopic.create(title: "The Blank One")
-    assert_nothing_raised do
-      BlankTopic.find_by_title!("The Blank One")
-    end
+    blank_topic = BlankTopic.create(title: "The Blank One")
+    assert_equal blank_topic, BlankTopic.find_by_title!("The Blank One")
   end
 
   def test_find_by_one_attribute_with_conditions