More CR feedback

This reverts commit b9dcaa13.

S.Collections.Immutable and System.Reflection.Metadata are seemingly
special: they're not inserted as Roslyn binaries and they're not
inserted as corefx packages. This means they won't get added to the
toolset package via either of the two previous mechanisms. Since
we don't have to worry about insertion into VS and things like binding
redirects, this change will just grab the binaries out of the output
of the build and place them directly in the output package.

Implements metadata import for tuple names in VB

Handle names correctly in long tuples in EE

add entry point related errors as build only errors

Merge future to master

Only declare Hidden Descriptors for SimplifyTypeName/QualifyMemberAccess

* Enable declaration patterns in the EE

Fixes #13159 

Properly handle expression variable declared within VariableDeclaratorSyntax.ArgumentList in field declarations.

Re-add property that internal CodeLens implementation depends on

Contains the Roslyn compiler build tasks and targets files.

Fixes #9640.

Fixes #12714

SimplifyTypeName, QualifyMemberAccess, and
CSharpUse[Implicit/Explicit]TypeDiagnosticAnalyzer were declaring one
DiagnosticDescriptor per DiagnosticSeverity level in SupportedDiagnostics.
After this change, they only initially report a DiagnosticSeverity.Hidden
descriptor, which prevents them from running on closed files.

There are longer-term plans to allow these to run on closed files but
under closer control of the user.

Display non-default Tuple names in EE

Consume [TupleElementNames] metadata in the EE ResultProvider and include element names in display strings.

Put in accessor accessibility modifiers when symbol display is asked to show read/write info for properties

Fixes https://github.com/dotnet/roslyn/issues/11016

Use appropriate telemetry key.

Reduce the number of objects allocated for SymbolTreeInfo.

Stop using UseCodebase for our product VSIXes

handle null argument list on invocation expression

Export persistence service at appropriate layer.

Now that we specify codebase attributes in our binding redirections,
we don't need this anymore. This allows ngen to work in more scenarios
since it resumes loading our packages in a Load context.

I leave our diagnostics window VSIX as is, since that's a debugging tool
and it's less to maintain by keeping it that way.