Reduce memory required for document change processing queues

Function pointer bug fixes

Microsoft.DotNet.Arcade.Sdk
 From Version 1.0.0-beta.20302.3 -> To Version 1.0.0-beta.20326.2
Co-authored-by: Ndotnet-maestro[bot] <dotnet-maestro[bot]@users.noreply.github.com>

* Additional tests for nested function contexts.
* Override VisitFunctionPointerLoad in MethodToClassRewriter.
* Adjust debug asserts.

Fix inconsistencies in handling CompilerVisibleItemMetadata

Perf improvement for completion of unimported extension methods

* Introduce LanguageVersion.CSharp9
* Limit netcoreapp3.0, 3.1 and netstdard 2.1 to C# 8.0
* Map CSharp9 to language version preview
* Default to CSharp9 for netcoreapp5.0
* Add Tests

Include line numbers in Integration Test stack traces

Fixes #45452

Fix failure to reuse pooled connections

Updates the option page type GUID to match the one in pkgdef

Correctly bind function pointer arguments for error recovery. Fixes https://github.com/dotnet/roslyn/issues/45418.

Track unrooted symbols in HashSet instead of ConditionalWeakTable

Correctly support local functions in function pointer loads. Fixes https://github.com/dotnet/roslyn/issues/45447.

Microsoft.Net.Compilers.Toolset
 From Version 3.7.0-4.20314.5 -> To Version 3.7.0-4.20319.6
Co-authored-by: Ndotnet-maestro[bot] <dotnet-maestro[bot]@users.noreply.github.com>

Fix descriptions for XMLDoc Triple Apostrophes in some languages.

Records need to provide a new form of source property symbol with
different syntax. This PR extracts a new base class to try to share as
much code as possible with the existing SourcePropertySymbol and the
SynthesizedRecordPropertySymbol.

Remove unnecessary conditional compilation

Update src/Features/Core/Portable/Completion/Providers/ImportCompletionProvider/ExtensionMethodImportCompletionHelper.cs
Co-authored-by: NCyrusNajmabadi <cyrus.najmabadi@gmail.com>

Refactor IDE open file diagnostic analysis + some perf improvements

Move SourceOrdinaryMethodSymbol functionality that is not syntax specific into a new base class. (#45424)

This work is related to #45296.

Don't fetch output paths for Intellisense projects