* unify DOCKER_TTY_ARGS in docker scripts
* improvements and cleanup in build_and_run_docker.sh
* fix shellcheck
* make sure python sdist artifact is readable
* Revert "Revert "Cleanup run docker machinery in run_tests.py, task_runner.py and elsewhere (#28704)" (#28741)"
This reverts commit 9a79d44e9b.
* fix python distribtest failure on fedora34
* attempt
* slim down build_docker_and_run_tests.sh
* HOST_GIT_ROOT is unused
* config and arch variable no need to propagate to run_tests.py
* unify unused LOCAL_GIT_ROOT to EXTERNAL_GIT_ROOT
* mounting gcloud config seems useless
* reorder docker args
* cleanup
* allow passing args to build_docker_and_run_tests.sh
* converge build_docker_and_run_tests.sh and build_and_run_docker.sh
* more convergence
* convergence of docker runners
* finalize convergence of run_docker scripts
* GRPC_TEST_REPORT_BASE_DIR might not exist
* adjust report copying
* make report_dir and output_dir readable
* alpine linux does not support cp -t
Change `git submodule` copying mechanism from the host
to the docker container to use `git clone` instead of
`git submodule update --init --reference`, which reaches
out to the network and fails on older docker containers
with deprecated openssl versions that do not support
modern TLS versions required by GitHub, e.g. manylinux1.
This fixes artifact builds for protoc and Python on Linux.
Jan Tattermusch