v4.x: backport of "test: refactor test-fs-non-number-arguments-throw"

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

Affected core subsystem(s)

test, fs, v4.x

Description of change

• Add RegExp arguments to throws assertions.
• Use common.mustCall for emitter callback.

PR-URL: https://github.com/nodejs/node/pull/9844