Forward arguments to `go test` in `bin/run-test`

To enable race detection (-race) or run only specific tests (-run $test), it's useful to pass extra arguments to go test. Currently this means we must choose between filtering out noise and controlling how the tests are run. This change makes bin/run-test forward its arguments (if any) on to go test, giving the best of both worlds.

"$@" is the safe way to forward script arguments; it is equivalent to "$1" "$2" "$3" and so on.