transport: add tests to verify that client/server sends RST_STREAM(NO_ERROR) if not half-closed when receiving trailers

[ejona86]

This is the client-side version of #834, to handle the case when intermediaries are in play. Note that the RST_STREAM can be elided if the server sent a RST_STREAM after the EOS=true. But the client can't assume the server will send such a RST_STREAM.

Java and C aren't doing this today, but there are issues for them: grpc/grpc-java/issues/2163 and grpc/grpc#7734.

[dfawley]

We are doing this (and the server-side RST_STREAM) but I don't believe we have tests for it -- I know we don't have tests for server-side, at least.