RFC: Test names printed in a friendlier blue colour

Previously we used red, which, as mentioned in #7557, might not be the best of choices for psychological reasons.  Instead, this patch uses the blue-ish `JULCOLOR` defined in `Make.inc`.  This is also the colour used for the `[stdio passthrough ok]` output in `test/spawn.jl`.

This PR is very much in line with my current trend of minor, trivial, patches due to a lack of time (**sigh**).  Hopefully sticking around will lead to greater contributions on my part.  Feedback is as always most welcome.