devtools/jiri-test: send tests to release-candidate-2-test with "part" suffix.
devtools/jiri-test: send tests to release-candidate-2-test with "part" suffix.

I've already updated release-candidate-2-test config to parse "partX"
from the test name and add the proper "part" flag to the "jiri test run"
command.

For example, vanadium-go-race-part1 will run:

jiri test run -part 1 vanadium-go-race

Change-Id: I6d70d60d776a26796d8f13a3bf6a0deae14edc4a

vanadium/go.devtools,vanadium/go.devtools,vanadium/go.devtools