Fixed a few find all refs bugs on values

[TIHan]

Since we changed the way we do find all references in VS, we had a few regressions. This should fix the ones mentioned here: #9863

For context, we risked regressions due to the significant memory reduction that came with the change. I'm sure there are more fixes to do; they should be relatively straight forward though.

The one thing with find all references that is not going to be straight forward is performing a find all references on a currently editing buffer (a file that is not saved yet). Unfortunately, a currently editing file is not consolidated to the way type checking works on a project as a whole; it's handled separately. We also have two different ways of getting symbol information, and that's determined if a construct is public or private.

One way to solve this is probably just implementing the FileSystem shim to forward to the editing buffer in VS, which is a giant hack. At some point, we should figure out how to make the F# compiler not rely on a file system; it should work directly with streams and/or buffers.

[cartermp]

fixes #9863, #9750, #8823

Note that the following are still issues with this PR:

• Rename duplicates the name when multitargeting #9275
• Find References incorrect output in VS 16.7 #9924
• Find all references doesn't work for references in Controller file in ASP.NET template #6243 (comment) (see comment)

[cartermp]

@TIHan I'm fine with taking this as-is for now since it does fix 3 distinct bugs. But there are 2 it still doesn't solve and an inconsistency in another. What are your thoughts?

[TIHan]

We should take the fix and keep iterating on the others.