Co-authored-by: NJason Malinowski <jason@jason-m.com>

Fix tests

Extracted from #41363
Third follow-up item from #41462

Apart from adding resx files, changes also include:
1. Moving resource strings duplicated across Workspaces and CodeStyle layer into the shared resx files
2. Source file changes to use the resource strings from the shared resx.

We should no longer require use of `#if CODE_STYLE` in the shared layer for the purpose of resource strings.

Extracts out the changes to core Workspace changes from https://github.com/dotnet/roslyn/pull/41363.

This adds nullable annotations to Document, TextDocument, the matching
States, and various helpers there too.

This code is assuming that given a token, we can chase up and find
a node that surrounds a span. Using FirstOrDefault meant if we couldn't
find one we'd pass null to GetSemanticModelForNodeAsync which would
promptly throw an exception. This will still throw exceptions but at
least will throw earlier.

I had to look at this code to understand exactly what can and can't
be nullable; since I think I've figured it out I'll annotate
accordingly.

* added NFW to get some data on incremental parsing bug where source size and tree size is different

* more comments

Failed TypeScript build:

https://devdiv.visualstudio.com/DevDiv/_git/VS/pullrequest/126057?_a=overview