benchmark: run.js output regression after d636fee319bc

[mscdex]

Version

main

Platform

n/a

Subsystem

benchmark

What steps will reproduce the bug?

./out/Release/node benchmark/run.js --format csv -- assert

How often does it reproduce? Is there a required condition?

Every time

What is the expected behavior?

Output should be in CSV format

What do you see instead?

"Normal" formatted output

Additional information

While d636fee seems to have fixed the truncated results output, it introduced a regression with explicit output formatting (and possibly other settings).

We need to add more tests to cover more of the benchmark runner's features, including output type.

/cc @ShogunPanda