* Remove the toolchains //third_party/toolchains:local and //third_party/toolchains:local_large.
* Remove the platforms :rbe_ubuntu1604, :rbe_ubuntu1604_large, :local and :local_large.
* No longer inherit from @rbe_default//config:platform but instead use it directly. It is now the only non-windows platform.
* When creating @rbe_default//config:platform directly with rbe_autoconfig, set dockerAddCapabilities and dockerPrivileged directly in the exec_properties field. No need to set dockerNetwork to "off" and dockerSiblingContainers to false since these are the defaults.
* Also set gceMachineType = "n1-highmem-2" on the default platform. This value can be overridden by specific targets that want to use LARGE_MACHINE.
* Use create_exec_properties_dict where appropriate.
* Use custom_exec_properties to define LARGE_MACHINE.
I wasn't able to test thoroughly that this PR does not break any existing targets. I was not able to run anything on windows/mac and I also don't have access to gRPC's RBE setup.
if the kokoro job times out and the bazel command is not done, it ends up in
weird test results ("Unevaluated targets") that are hard to interpret.
Setting the timeout for kokoro jobs high enough to create extra reserve
should help.