errors, child_process: migrate to using internal/errors

Ref: https://github.com/nodejs/node/issues/11273

Semver-major because error messages are changed.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

errors, child_process