Remove addParserOutputMetadata() from formHTML(), add it to callers as necessary

This will fix the issue where JavaScript parts of inputs are called twice.

Tried and works for
* action=formedit
* Special:FormEdit/Form (1-click page creation)
* Special:FormEdit/Form/Page (page editing)
* Special:RunQuery
* transposed Special:RunQuery
* preview of page containing transposed Special:RunQuery

Does not work for
* preview of Form editing (did not work before either)

Change-Id: I9dd224da28a06e624ecddf138d58715698e49422