GeezerVison

What does this implement/fix? Explain your changes.

Converting a CLR value to Python can throw after the call has succeeded, eg if an encoder's TryEncode throws, or if calling enumerator.Current throws. Previously the exception was never converted to a Python exception making it uncatchable even instead, so Python code could not catch it, not even using except BaseException

• MethodBinder.Invoke guarded only the invocation, and converted the result and out parameters after its try/catch
• Iterator.tp_iternext guarded MoveNext but not Current or the conversion of the item
• ArrayObject indexing converted items with no guard at all

Each now reports the failure through Exceptions.SetError, as the existing catch already does for the call itself. Property and field getters already convert inside their try and are unchanged.

Checklist

Check all those that are applicable and complete.

• Make sure to include one or more tests for your change
• [n/a] If an enhancement PR, please create docs and at best an example
• Ensure you have signed the .NET Foundation CLA