[FEATURE REQUEST] Parallel test running option

[amgross]

Add utility of -jXX to run the unit tests (that anyway running in separate process) in parallel.

To avoid prints that will mix together, need that the processes won't write to stdout but will write to other place and just upon termination it will be copied to stdout. In case of no parallel, the output should go to stdout.

This change should be as light in runtime as can so it will really gain better time even for short tests.

[edsiper]

we have the similar need, "one" of our unit tests is pretty long:

https://github.com/fluent/fluent-bit/blob/master/tests/runtime/out_stackdriver.c#L6540-L6675

it seems the option we have is to put every test in a different file to generate a different binary but sounds not optimal..

wondering if @mity has considered including some parallel test support

[amgross]

Well, you don't must create different binary, with acutest you can decide which test to run in the command line (no wlspecifiyng any test running all).
Hence you can create wrapper script that running multiple instances of acutest tests in parallel, each one with different test