Add fuel test and benchmarks for empty scripts

[jeffcharles]

Description of the change

Adds a fuel test for an empty JS file and a benchmark for an empty JS file. Also updates the benchmarking suite to use javy build.

Why am I making this change?

I realized we're missing performance tests for empty scripts so we can assess if a change adds noticeable additional overhead or not.

Checklist

• I've updated the relevant CHANGELOG files if necessary. Changes to javy-cli and javy-plugin do not require updating CHANGELOG files.
• I've updated the relevant crate versions if necessary. Versioning policy for library crates
• I've updated documentation including crate documentation if necessary.