TBR: jiri-test/internal/test/create_instance.go: Add Env Var for project.
TBR: jiri-test/internal/test/create_instance.go: Add Env Var for project.

Add an environment variable to select the project where the test
instance is running.

Change-Id: Ia13de23862417b62e71cfe1315b46dc1106c4be7

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