[surface] Ensure SEND_STATUS & RECV_MESSAGE do not inhabit the same batch

[ctiller]

Add a check that SEND_STATUS_FROM_SERVER and RECV_MESSAGE are not in the same batch.

This is necessary pre-work for #31204 and implements part of grpc/proposal#336.

Also eliminates fling instead of updating it:

• My expectation is nobody has looked at this corner in many years
• It's not a benchmark we want: concentrating on a microbenchmark that doesn't include a binding layer caused us to favor designs that emphasized a lightweight core at the expense of a expensive bindings. We should consider the whole.

Tagging @markdroth for C/C++, @apolcyn for Ruby, @gnossen for Python, and @stanley-cheung for PHP changes.