fixup! component/nxdtest: Prepare for nxdtest!13
Fix the following build failure in nxdtest's own test:
[2021-12-10 15:57:15,142] INFO While:
[2021-12-10 15:57:15,142] INFO Installing.
[2021-12-10 15:57:15,142] INFO Getting section python-interpreter.
[2021-12-10 15:57:15,142] INFO Initializing section python-interpreter.
[2021-12-10 15:57:15,142] INFO Getting option python-interpreter:eggs.
[2021-12-10 15:57:15,142] INFO Getting section nxdtest.
[2021-12-10 15:57:15,142] INFO Initializing section nxdtest.
[2021-12-10 15:57:15,142] INFO Getting option nxdtest:eggs.
[2021-12-10 15:57:15,142] INFO Getting section .nxdtest.pyexe.
[2021-12-10 15:57:15,142] INFO Initializing section .nxdtest.pyexe.
[2021-12-10 15:57:15,142] INFO Getting option .nxdtest.pyexe:eggs.
[2021-12-10 15:57:15,142] INFO Getting option nxdtest:eggs.
[2021-12-10 15:57:15,142] INFO Getting option .nxdtest.pyexe:eggs.
[2021-12-10 15:57:15,142] INFO Error: Circular reference in substitutions.
This is hot, not a proper, fix to recover nxdtest.UnitTest-Master status.
I will think more calmly what to properly do.