Refine implementation of retry in dotnet test

[nohwnd]

dotnet/sdk#48075 this PR parses out the info about retry from commandline, and instead it should be told by the platform that retry is happening and only react to the messages.

Probably on the assembly start we want to have retry: true, and try: number, when retry is being used.

[Youssef1313]

Sadly, moving out of .NET 10 as it's pretty late now. Regarding design, I think what we need here is simply that the orchestrator handshakes with dotnet process, with a special property indicating "retry" functionality. In addition, it might be best if we can get rid of InstanceId stuff that we added, and instead encode the "attempt number" as part of test result messages. But that itself needs a design on how we can approach it (e.g, well-known env variables that are read by the protocol?)

[Youssef1313]

Related (possibly one can be closed as dupe of the other): #6337