Use mojo-executor

[basil]

Addresses this long-standing comment from commit commit ee161c7:

All I want to do here is to invoke the hpl target. there must be a better way to do this!
jglick: perhaps https://github.com/TimMoore/mojo-executor would work?

Indeed, it would.

[jglick]

Looks right, and evidently

maven-hpi-plugin/src/it/parent-3x/invoker.properties

Line 3 in 5d3d4cd

invoker.goals=-Dstyle.color=always -ntp -Pjenkins-release -Drelease.skipTests=false clean install hpi:run

passes.

[basil]

I also tested this interactively.