Closes #30171.
Closes #29838.

* Remove RuntimeIdentifier specification

* Arcade directory layout

Standardize the conditional IOperation verification skip method, and fix a bug that caused it to skip in exactly the wrong way.

Merged on behalf of @maca88

* Added UseOriginalEndOfLine option on SyntaxRemoveOptions to preserve the EOL from the original node (#22924).

* Grammar correction.

* Removed the normalizer parameter

* Removed UseOriginalEndOfLine from shipped api

* Added UseOriginalEndOfLine to unshipped public api

* Added a null check in AsRootOfNewTreeWithOptionsFrom method

* Removed HasEndOfLine method in favor of GetEndOfLine to avoid duplicate calls.

* Modified KeepEndOfLine option to add an EOL for a directive only if there is one in the original document

* Modified KeepEndOfLine option to preserve the EOL from the original node and removed UseOriginalEndOfLine option.

* Modified AddEndOfLine method in order to avoid code duplication

* Minor modifications

* Added more tests and removed unneeded GetEndOfLine calls

* Added a static method to test both Windows  and Unix EOL and used where it matters.

* Added a fallback EOL when requiresNewLine is set to true

* 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

This change simplifies our data flow analysis by removing an obsolete subclass and renaming some of the components to standardized names used in the literature on lattice data flow analysis.

Fixes #23207 

[CHANGED] Removed the filepath from the filename of the log. The loggingFileName could be "C:\Users\user\build" which means that the second string in Path.Combine generates to "server.C:\Users\user\build.log" and that will be combined with the path once again leading to a full file path of: "C:\Users\user\build\server.C:\Users\user\build.log" and I dont think thats legal on Windows.

Don't warn about "!", regardless of context (https://github.com/dotnet/csharplang/blob/master/meetings/2018/LDM-2018-10-29.md).

Closes #30177.
Closes #30021.

Preserve non-nullable state of a value that is going through explicit conversion to an unconstrained type parameter.

Handle unconstrained type parameters in conditional operator.

Explicitly pass NullableAnnotation value to TypeSymbolWithAnnotations.Create method.

Handle unconstrained type parameters in conditional access.

Handle unconstrained type parameters in “As” conversion operator.

Remove obsolete APIs from TypeSymbolWithAnnotations

Closes #30050.
Closes #30051.

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

 Adjust the way nullable annotations are represented in metadata.

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