Rename ReplaceableAttributeSetter to ForceSetAttributeOnThis in bindings generation

This is also used for constructor attributes. Removing 3 FIXMEs.

BUG=345503

Review URL: https://codereview.chromium.org/339073005

git-svn-id: svn://svn.chromium.org/blink/trunk@176717 bbb929c8-8fbe-4397-9dbb-9b2b20218538