Revert "use the source instead of the name to find nuget packages"

This reverts commit 0d8d2afb.

Skip BasicEditAndContinue tests

- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19326.2

Related to #35619.

Fix GetHashCode on constructed types with annotated type arguments

Conflicts:
	src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs

Handle lazy loading of analyzer command handlers

Add workarounds to IDE analyzers for missing IOperation/CFG support for using declarations

- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19324.24

Pass feature flags to the remote workspace

Nullable Analysis Pay-for-play

Fix typo in task namespace in docs

* Correctly report nullability of tuples in the semantic model:
- Store the original tuple literal rather than just its type
- Visit the original literal without diagnostics only in the nullability walker to understand its type
- Update the generator to allow force visiting fields in the nullable re-writer
- Update type checker to allow checking of converted types too
- Update various tuple tests to be correct
- Add extra tests

This implements IExperimentationService in the remote workspace; any
request for feature flags is forwarded to the main Visual Studio process
and the feature flag is queried there.
Co-authored-by: NJoey Robichaud <jorobich@microsoft.com>
Co-authored-by: NHeeJae Chang <hechang@microsoft.com>

Couple of AD0001 fixes for unused parameter analyzer

Unwrap nullability-wrapped symbols in object initializer completion 

Fixes #36304

Fixes #33464

Workaround for #32100 for Dev16.2

Fixes #34830

Fixes #36715

This slipped through because we didn't have any tests at all for
the case where we are using the type-inferrer to infer the case like:

    a = new A { B = { } }

where the inner one doesn't have a new B before it. The scenario wasn't
new but just happened to be the precise case that was broken.

Fixes https://github.com/dotnet/roslyn/issues/36702

Fixes #30324

razor added new @code block. add support for new code block in roslyn.

for old razor version, IsCodeBlock won't get called since razor will not treat code in @code as C# code block, in new razor version where @code is added, razor will recognize it as C# code block and call us which we will in turn check new @code along with existing @ tags for code blocks.

enabled the nullable feature, either on the command line
or via a nullable enable directive.

Not sure why these are lowercase but makes the tests harder to read.

Make Dispose analyzers (IDE0067 and IDE0069) more conservative

Fixes #34483, #36112

Change dotnet_diagnostic.*.severity settings to match code style