Make ASSERT_NO_EXCEPTION and AttachLazily the default arguments for insertBefore, appendChild and replaceChid.

Eventually, we'll get rid of DeprecatedAttachNow entirely and remove AttachBehavior
as an argument.

Review URL: https://chromiumcodereview.appspot.com/23382006

git-svn-id: svn://svn.chromium.org/blink/trunk@156520 bbb929c8-8fbe-4397-9dbb-9b2b20218538