test: remove unused var from child-process-fork
Checklist
-
make -j4 test
(UNIX), orvcbuild test nosign
(Windows) passes -
tests and/or benchmarks are included -
commit message follows commit guidelines
Affected core subsystem(s)
test child_process
Description of change
messageCount
is assigned, but never used. Remove it.
(This was missed by the linter in previous versions of ESLint but is flagged by the current version. Updating the linter is contingent on this change or some similar remedy landing.)