[Feature Request] - Create benchmark for Object creation and access

[jasonwilliams]

In order to test the upcoming optimisation work we're doing around objects it would be good to have a benchmark for objects so we can see a before and after.

Example

Benchmarks live here
an object creation and access would be categorised under exec.

You can see the fibonacci benchmark here:
https://github.com/boa-dev/boa/blob/master/boa/benches/exec.rs#L49-L66

2 benchmarks could be made, 1 for accessing a value from an object, another for creating an object.

in order to run the benchmarks you can run cargo bench in the root folder

Contributing

https://github.com/boa-dev/boa/blob/master/CONTRIBUTING.md
https://github.com/boa-dev/boa/blob/master/docs/debugging.md