Rework assert.multiple behavior under debugger to throw on each failure

[MaceWindu]

Fixes #4738.

Instead of throwing on first failure, we will generate catched exception on each failure to allow user to debug it and still have multiple assert exception in the end

[OsirisTerje]

@manfred-brands @stevenaw Can you have a look?

[manfred-brands]

github doesn't allow me to comment on non-changed code.

@MaceWindu Should the ThrowOnEachFailureUnderDebugger property not be copied in the TestContext copy constructor?

Every child in a CompositeWorkItem aka a Fixture gets a new TestExecutionContext.
But the child will not have ThrowOnEachFailureUnderDebugger set, ever.

The only place where it is currently set is in the NUnitTestAssemblyRunner.

@OsirisTerje Not all the other properties are copied either.
TestCaseTimeout and StopOnError are, but Current(UI)Culture are not. Should they?

[OsirisTerje]

@MaceWindu See comments from @manfred-brands - any upcoming action on those?

@manfred-brands Not all the other properties are copied either.
TestCaseTimeout and StopOnError are, but Current(UI)Culture are not. Should they?

Good question, meaning, IDK. I don't think they are being asked for, on the other side, it should not do any harm if they do.
I also noticed that over time we have added properties to TestContext from underlying classes, and they have not been documented. (Did that now)., So perhaps we should do a separate cleanup and documentation issue on that?

[MaceWindu]

@OsirisTerje , I'will add copy of those properties. Just tested and can confirm options are not propagated to test context

[MaceWindu]

BTW, CurrentCulture and CurrentUICulture not copied, as they are calculated properties over _sandboxedThreadState, which is copied already

[OsirisTerje]

Ok, seems all is done here.

[stevenaw]

Thanks @OsirisTerje
Had just been looking to approve this myself 👍