Test result page occaisionally identified tests as age 1.

If a test has not been viewed, the age will keep being 1.
This is because getFailedSince()/failedSince is lazy loaded.
Without having viewed the ScenarioResult that method is never
called and the prev.failedSince returns '0' which may or may
not be accurate.

from which this change was identidied
see also https://github.com/jenkinsci/jenkins/commit/bffca9cd0610d97d532919d8fdd8a0fff5a31b1f#diff-3bcaa7a7a5b2c0cf45fbc592305beb75R298