* Use Arcade testing targets

* Skip CodeStyle tests on Mono

* Include net472 in test target frameworks for Mono

* Remove incorrect file existence check.

* Update ADO integration test yaml

* some code clean up and added some code instruments to make perf investigation easier

* changed lambda to local function and addressed feedback

* Classify malformed XML Doc comments as XmlDocCommentText

* Added test for malformed xml doc comment classification

* Updating classification for discard designation and underscore tokens to be Keywords rather than Identifiers.

* Removing underscore from the IsKeywordKind check, since it is covered by isContextualKeyword

* Reverting change to SyntaxFacts and moving discard check back to ClassificationHelpers.

* Reverting all changes to SyntaxFacts.

* Add a comment clarifying how _ is classified.

make sure to VS and OOP to use same file to get mvid of analyzer file reference when creating checksum for both VS and OOP (#31438)

the problem is that the OOP always used the actual file that got used for analyzer (in other words, shadow copied file in VS), but VS used original file to get MVID.

based on shadow copying logic, 2 (with same assembly identity) might actually be 2 different files by sharing a shadow copied file between 2 original files with same assembly identitis causing MVID to be different.

this make sure all use same file for MVID so that regardless of host implementation of analyzer loader (who is the actual thing that control what file will be used to get analyzers), we get consistent MVID

Related issue: https://github.com/dotnet/roslyn/issues/25145
This PR add the function to VS and let use to pull members up via quick action

Reverts the changes to Hash.cs from #31276 and unlinks the file from the
Code Style layer.

Fix an assert introduced my previous commit for conservative analysis in presence of delegate type arguments, where parameter default value is used instead of an explicit delegate argument. This was causing the fast pass (operation tree based symbol usage analysis) to bail out, while the slow pass (control flow graph based symbol usage analysis) to correctly identify and flag unused values.

Conservatively handle delegates passed as arguments to method invocations by reseting state so all the current writes are assumed to be read.
Also ensure that we report unused parameters when we bail out from flow analysis, as the latter should only prevent us from reporting unused values.

1. Do not invoke SyntaxEditorBasedCodeFixProvider.FixAllAsync if there are no diagnostics to fixed.
2. Handle flow captures that are both lvalue and rvalue captures (left of a compound assignment operation where right has conditional code).

 Adjust the way nullable annotations are represented in metadata.

Closes #30075.
Closes #30065.
Closes #29594.
Closes #29683
Closes #29662

This reverts commit 166349c8.