test: fix single test runner regression
Alternative to https://github.com/nodejs/node/pull/15300.
/cc @apapirovski
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarks are included -
commit message follows commit guidelines
Affected core subsystem(s)
test
Refs: https://github.com/nodejs/node/pull/15300. Refs: https://github.com/nodejs/node/pull/14369