We now build all packages (including //test/...) with RBE as part of the Kokoro
presubmit.
The tests do not yet use RBE, because there are some failures. The Golang unit,
integration, and image tests still run locally.
The syscall test suite needs even more work to make it pass on RBE. Those will
be enabled in follow-up CLs. They currently are not enabled at all on Kokoro.
PiperOrigin-RevId: 226562208
Change-Id: Idd2b81b3e8f07bf300c77e68990493ba97d16e23