src: use more appropriate context-entered check
Make the context check in MakeCallback
match what the comment says
(and what actually makes sense).
Fixes: https://github.com/nodejs/node/issues/15672 Ref: https://github.com/nodejs/node/pull/15428 Ref: f27b5e4b
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarks are included -
commit message follows commit guidelines
Affected core subsystem(s)
src