test: move common.onGC to individual module
Incrementally making require('../common')
less of a monolith.
Move the common.onGC()
utility to a separate standalone module
that is only imported when it's actually needed.
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarks are included -
documentation is changed or added -
commit message follows commit guidelines