serialization

…hout a cached result

…ith current implementation

… completion state matches

…ike a resultId we can pass between the client and server

…ed builds inside Visual Studio

Work towards [AB#1337109](https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1337109)

For builds which are indirectly triggered inside Visual Studio from commands such as 'Run Tests' or 'Start Debugging', we implicitly skip analyzers to speed up these builds.

Such builds will set a special property `IsIndirectlyTriggeredBuildInsideVisualStudio` to `true`, which guards the implicit skip analyzers logic. We display a special message to inform the users about us implicitly skipping analyzers to speed up the build.

To enable MSBuild's incremental build logic and project system's fast-upto-date check logic to work correctly, we create/touch a special semaphore file to indicate the time stamp for last build with skipAnalyzers flag. This semaphore file is passed as a custom additional file input to builds without skipAnalyzers flag to ensure correct incremental builds. Additionally, we pass this file as an 'UpToDateCheckInput' item for project system's fast-upto-date check.

Fixes #54038

Ideally ImmutableSegmentedHashSet<string> would be used, but this type
is not currently available. As an interim solution,
ImmutableSegmentedDictionary<string, VoidResult> is used as a set.

See https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1343268

Fixes #54159

Use segmented collection for faster declaration cache

Add functionality to enable skipping analyzers for implicitly trigger…

* Allow snippet format in XAML compeltion

* change InsertSnippet to IsSnippet

* fix formatting

Fixes #53769

Handle tokens with Kind == None in argument completion

Optimize calculation of remote supported languages

Initialize MEF services before switching to the main thread

Use isIncomplete flag to cap the LSP completion list size for faster serialization

… 20210618.1 (#54219)

[main] Update dependencies from dotnet/source-build