Prevent embedding of non-abstract interface members.

Closes #35852. Closes #35911.

Move some ComputeRefactoringsAsync to common helpers 6/n

Fixes #37713

Merge master to release/dev16.4-preview1

Disabling Mono leg

Latest Mono nightly builds appear to have broken serialization during
remoting across AppDomain instances. That is pretty fundamental to how
we test. Temporarily disabling the Mono leg until this can be fixed.

Tracking Mono Issue: https://github.com/mono/mono/issues/16373

Give LangVersion error when type is generic due to parent type

VB: Support protected access for interface members.

Closes #35827.

Add generation for all IOperation nodes

Fix typo

Use ImmutableInterlocked.InterlockedInitialize instead of CompareExchange with default, minor formatting and naming suggestions.

Fixes #37461

Annotate SymbolInfo and TypeInfo

Fix Metadata as Source caching stale generated files

Treat parameters and local variables as having the default state for their type before they are assigned. (#37762)

Fixes #36052

Revert "Adding Null Checks For All Parameters"

Ensure that OriginalXSymbols are copied over when enabling nullability.

Add missed space in markdown title

We've published intermediate 3.3.0 packages for some early consumers,
so our final shipping version will be 3.3.1.

[master] Update dependencies from dotnet/arcade

- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19416.16

We maintain a cache of assembly file names and symbols to the generated
file. We failed to ever include a version of some kind, so if the
metadata file changed on disk, you would continue to get the old
generated file.

Closes #38010.

This fixes a crash when we successfully resolve the overload of the Equals method being called but there are not enough arguments to it. In practice this means that only object.ReferenceEquals which is not overloaded would crash VS. Also fixes the same issue in CompareExchange analysis which could crash if it was only declared it with one overload.