I know this is an unimportant change, and that across Chromium,
"try job" and "tryjob", and "try bot" and "trybot" are basically
interchangeable, still I think it's nice to have the spelling
consistent within one module.

I prefer the version with a space just because that's what's used
in the documentation:
https://www.chromium.org/developers/testing/try-server-usage

Review-Url: https://codereview.chromium.org/2269283002