[BUGFIX] Make standard-search working with EXT:form installed

The standard-search relies on basic form-functionality.
But if EXT:form is installed, that functionality is overlaid
and the result is wrong.

Provide a flag so that standard-search can request to use
the "basic" form-functionality, preventing EXT:form from
dealing with it.

Change-Id: I52cbd6cecc7222217ff766393dd37ad9d1a9aa30
Resolves: #50274
Releases: 6.2, 6.1
Reviewed-on: https://review.typo3.org/28042
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind
Reviewed-by: Jigal van Hemert
Tested-by: Jigal van Hemert