This is for the same reasons as ParseJson, that is so that we can limit
the scope of the proto namespace differences between internal and
external.

Server was continuing to make requests for new calls forever, which were
starving out the shutdown sequence. Change order and win.

C core automatically shares subchannels between channels. Therefore our
multiple channel performance tests were really testing single channel
performance.

input

distributions since we don't use them and it's not sensible
to add them

Run those json configurations as part of presubmits

payload config in our server config. This affect any generic server
tests that use anything other than 0-byte responses: essentially,
server-streaming or bidi throughput tests.