* update win RBE docker image and toolchain
and switch win RBE builds to using it.
* delete legacy RBE windows toolchain config
* switching to VS2019 makes #28544
* Add bazel cpp distribtest for grpc_cc_library
* Add new directory to bazelignore
* Try changing to workspace differently
* Debug cd
* Fix bazel wrapper
* Yet more debug
* Try again
* Clean up
* Sanity fixes
* Run per-language distribtests even if overall build fails
* Make repo globally buildable
* Add initial distrib test script
* Add test script
* Support multiple versions
* Split out a separate latest version test
* Integrate with kokoro
* make tools/bazel version overridable
* added simplified test_single_bazel_version.sh
* cleanup .bazelignore
* only test 3.x and 4.x
* always test all the bazel versions
* revert unnecessary changes
* revert unnecessary changes
* fix shellcheck error
Co-authored-by: Richard Belleville <rbellevi@google.com>
Esun Kim
Jan Tattermusch
Richard Belleville
Jan Tattermusch