The custom_metadata test uses response_parameters for FullDuplexCall

Enable advanced Java interop tests

Use `grpc_closure`s in `grpc_timer`s

Start some performance notes

FullDuplexCall

Add response parameters to custom_metadata streaming request for Node and PHP
clients.

The Java server does not respond with separate initial and trailing
metadata when there is no response data - it is only emiting the
requested trailing metadata. Adding the response parameters to the test
(in accordance with the specification) avoids this, but I will open a
separate issue to investigate the Java behavior.

Support long grpc-messages on abnormal close path

Adding Bazel tests.

Fix slice/exec_ctx interactions

Ruby Advanced Interop Server Side

Fixing submodules sanity.

Faster test building: avoid repeated linking

Bazel integration

Fixes for tests

Fixes for tests

Remove old fixture