…17.10

#### AI description  (iteration 1)
#### PR Classification
Code cleanup and new feature.

#### PR Summary
This pull request includes code cleanup, new tests, and the addition of new YAML templates for generating SAS tokens and federated access tokens.
- `src/Features/CSharpTest/EditAndContinue/TopLevelEditingTests.cs`: Added new tests for class implementations of interfaces with various method types.
- `src/EditorFeatures/Test2/Diagnostics/DiagnosticServiceTests.vb`: Removed the `TestTryAppendDiagnosticsForSpanAsync` test.
- `eng/common/templates-official/steps/get-delegation-sas.yml` and `eng/common/templates/steps/get-delegation-sas.yml`: Added new YAML templates for generating SAS tokens.
- `src/Features/LanguageServer/Protocol/Features/Diagnostics/EngineV2/DiagnosticIncrementalAnalyzer_GetDiagnosticsForSpan.cs`: Refactored method to use `LatestDiagnosticsForSpanGetter`.
- `src/EditorFeatures/Test/Structure/StructureTaggerTests.cs`: Added a new test to verify if statements should be collapsed.

…dev/shech/updateSTJTo8.0.5In17.10

Update STJ

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#### AI description  (iteration 1)
#### PR Classification
Dependency update

#### PR Summary
This pull request updates the `System.Text.Json` dependency and modifies a NuGet package source URL.
- `NuGet.config`: Updated the URL for the `darc-int-dotnet-runtime` package source.
- `src/Workspaces/Core/MSBuild.BuildHost/Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.csproj`: Updated `System.Text.Json` package version from 8.0.4 to 8.0.5.

…ev17.10' into merge-from-internal-17.10