Closes #30171.
Closes #29838.

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

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 

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.

 Adjust the way nullable annotations are represented in metadata.

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

Moved C# to not pass multiple children to constructors, and instead just pass the original bound node.

Add tests to demonstrate that they are associative and commutative.
Add (skipped) tests to demonstrate that we have inconsistent meet and join functions.
    We will have to decide how to handle the differences.
I have not yet extracted the NullableState operations from ConversionsBase
    (e.g. testing if one NullableState is higher or lower than another in the lattice)
Also removed some inoperative code in MethodTypeInference

Fixes #30561

* Add sdkPath option to CSharp

* Simplify sdkPath test in CSharp

* Add tests for VisualBasic sdkPath switch

* Add MSBuild FrameworkPathOverride property to CSharp based on VisualBasic precedent

* Add Vbc SdkPath switch test

* Add WorkItem tags to CommandLineTests.cs

* Add /sdkPath- switch

* Add tests for multiple /sdkPath arguments

* Remove extra blank line from CommandLineTests.vb

* Update command line doc

* Add /sdkPath- and tests to VisualBasic

* Update C# and VB compiler help

* Remove /sdkPath:<file> switch from CSharp

* Update doc

* Update Csc task and test

* sdkpath- -> nosdkpath

* Add DisableSdkPath property to VB targets

* Update tests

* Add NoSdkPath tests which attempt to reference System.dll

* Disable ResourceTests.AddResourceToModule in Mono

* Only run DestructorTests.BaseTypeHasNonVirtualFinalize on WindowsDesktop

Remove NonNullTypes context and other unnecessary information stored in TypeSymbolWithAnnotations. (#30913)

Remove NonNullTypes context and other unnecessary information stored in TypeSymbolWithAnnotations.

Fixes #30845.

Explicitly handle nullability analysis for unconstraint type parameters.

Related to #29981, #29993