Merge pull request #9120 from soltanmm-google/if-you-run-away-from-things-it-just-means-you're-going-to-see-them-again-when-you-wrap-around-the-universe

Fix Python setup-time diagnostics

C++ filter API cleanup

Client channel init cleanup

HTTP/2 test server

Fix building protoc artifacts on linux

gRPC CLI parse, tobinary, totext commands

Add GRPC_CONTEXT_TRAFFIC in grpc_context_index

Patch overlooked strings from Python un-namespacing

Add xmldoc comments for function arguments in generated C# code

Remove leading space in C# service comments

Short deadlines: set Status on deadline

Fix typo

Revert "Add configurable exit grace periods and shutdown handlers"

Un-namespace Python packages

Uses dynamic loading to paper-over the negative effects of losing
namespace packages in the previous commit.

Revert "Reduce memory bloat (each server cq is very expensive)"

Reduce memory bloat (each server cq is very expensive)

Setuptools was updated and our hacky namespace-package-chickens came
back to roost. This removes the unsupported namespace package hacks.