tools/lib/runutil: make TestTimedCommandFail and TestTimedCommandWithOptsFail less flaky.
tools/lib/runutil: make TestTimedCommandFail and TestTimedCommandWithOptsFail less flaky.

- Separate build from run.
- Increase timeout a little bit.

Change-Id: I5ac3a3655e54e09ded12df857e5e60967649b317

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