benchmark: add --expose_internals switch

[bzoz]

Checklist

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

Affected core subsystem(s)

benchmark

Description of change

Adds --expose_insternals switch to benchmark runner. This makes misc/freelist.js and any other benchmark requiring access to internal modules run properly on Windows.

cc @nodejs/benchmarking