import configurable git protocol changes from NQP

Fixes RT #121072
show "Any" in Parameter.gist

This seems to be wanted.
allow definition of custom postcircumfixes
strip "return" if the thing to return is the last
Generalize create-moar-runner.

Means we'll be able to use it to create a perl6-debug one also.
Add perl6-debug into MoarVM build.