* Abstract the SSPI context generation
This change introduces SSPIContextProvider that can generate payloads for SSPI. Specifically, this change plumbs the current SSPI context generation into this object, while later changes will continue to update the shape to be a more general purpose, public API.
- A successful sample run can be found with the non-official template [here](https://dev.azure.com/SqlClientDrivers/ADO.Net/_build/results?buildId=82875&view=results) without SDL tools.
- There are a few errors reported by code analyzer that need to be addressed as well.
- Due to the known issue with APIScan and Onebranch, it's temporarily deactivated.
Related work items: #28134
**Description**: While doing some investigation into improving the diagnostic tracing tests, I noticed that test failures are logged very non-descriptly by remote executor. To resolve this issue, we have to downgrade xunit to v2.4.2. Here's the rationale for this change:
* RemoteExecutor throws `XunitException`s from xunit.assert nuget and uses the `(string, string)` constructor
* The `(string, string)` constructor was removed in >=2.5 of xunit.assert
* RemoteExecutor was fixed to inherit from Exception in newer versions, but for us to take this requires upgrading to .net 7 or 8 (which I imagine is a much larger lift)
* In order to downgrade xunit.assert, we need to downgrade xunit
* In order to downgrade xunit, we also need to downgrade Microsoft.DotNet.XunitExtensions
* Without this change, exceptions from RemoteExecutor will fail to construct, masking all errors with "MethodNotFound"
Although normally downgrading is bad for security reasons, I believe this to be a safe change since it only affects tests.
This PR also makes a bunch of improvements to the `DiagnosticTest`s:
* Remove conditional facts when test TDS server is used
* Remove try/catch with empty catch block, replace with assert.throws
* Ensure that connections are opened before trying test conditions
* Document scenarios where test TDS server doesn't obey actual behavior, or where test TDS server cannot be used
* Formatting improvements
**Testing**:
* All tests (that are expected to pass) continue to pass
* In a synthetic failure of diagnostic tests, here's the before and after of the error messages:
* Before:
```
System.MissingMethodException: Method not found: 'Void Xunit.Sdk.XunitException..ctor(System.String, System.String)'.
System.MissingMethodException
Method not found: 'Void Xunit.Sdk.XunitException..ctor(System.String, System.String)'.
```
* After:
```
Microsoft.DotNet.RemoteExecutor.RemoteExecutionException: Remote process failed with an unhandled exception.
Microsoft.DotNet.RemoteExecutor.RemoteExecutionException
Remote process failed with an unhandled exception.
Child exception:
Xunit.Sdk.FailException: Assert.Fail(): Foo
at Microsoft.Data.SqlClient.ManualTesting.Tests.DiagnosticTest.<>c.<SyntheticFailure>b__1_0() in
C:\Projects\benrr101\sqlclient\src\Microsoft.Data.SqlClient\tests\ManualTests\TracingTests\DiagnosticTest.cs:line 34
```
## Commits
* Downgrade xunit for better error logging from remote executor
* All but one test improved ... ?
* Understanding why test was failing
* Add arcade and xunit nugets to .net8+ special versions
* Remove xunitextensions version boost (which I spelled wrong anyhow)
Evgeny Akhtimirov