test: replace `indexOf` with `includes`
Refs: #12586 (closed)
Tests Updated:
- test/parallel/test-http-client-agent.js
- test/parallel/test-http-client-default-headers-exist.js
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