Fixes #38819

Delete a bunch of code on Roslyn side, which is no longer necessary as we don't own the column anymore.
I have also cleanup up some code in this space for newly added ContainingType and ContainingMember columns.

Adds the definitions for the nullable attributes and creates an
annotated Debug.Assert

* Both columns added

* Genericize custom column names

* More changes to genericize

* Cleanup

* Respond to feedback

* WIP

* Change tuple to properties

* Restrict to just containing types

* Cleanup

* cleanup

* Refactor

* Change method for getting Containing Type and Member

* refactor GetAdditionalProperties

* Fix merge conflicts

* respond to feedback

* respond to feedback

* Change to struct

* Add type for AbstractCustomColumnDefinitionWithMultipleValues

* Cleanup

* Change AdditionalProperty to FindUsagesProperty

* respond to feedback

* respond to feedback

* Hide columns in F#

* respond to feedback

* fix merge conflict

* Change from hiding columns to removing columns for non supported langs

* Add additional implementations

* formatting

Co-Authored-By: NSam Harwell <sam@tunnelvisionlabs.com>

Refactor code, add unit test and ensure that we use different block analysis data instances for fall through successor and conditional successor.

We were allocating large number of BasicBlockAnalysisData instances during Merge operations when performing symbol usage analysis for locals/parameters, and holding onto these until the whole method has been analyzed before returning them to a shared pool. This approach works fine for most cases, except for extremely large methods with large number of local variables, such that the analysis needs multiple flow analysis iterations over the CFG.
This PR fixes this issue by returning the allocated BasicBlockAnalysisData instances during Merge operations immediately back to the shared pool. I also added another optimization to reduce the size of tracked per-basic block analysis data by removing tracking locals as and when they go out of analysis scope.

Fixes #38650

Closes #36930
Closes #38587

* EnC: fix handing added and design-time-only files

* Fix nullability warnings

* Fix nullable warning

tweaked a bit more so that we dont run anything on UI thread for syntactic classification

add latency tracker to the new tagger