DOC: Projected time for running entire performance test suite is outdated
#### Location of the documentation

https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#running-the-performance-test-suite

**Note**: You can check the latest versions of the docs on `master` [here](https://pandas.pydata.org/docs/dev/).

#### Documentation problem

Ran entire performance test suite for #36161 and it took close to 8 hours. Docs state: "Running the full test suite can take up to one hour and use up to 3GB of RAM". From @jreback I understood that this is because the test suite has increase a lot in size, since the last doc update.

#### Suggested fix for documentation

I would add a disclaimer regarding your hardware and state that running the tests on a laptop can take up to X hours. For X we can take 8 or another number if others have experienced an even longer duration for running the full performance test suite. So we end up with something like this:

"Projected duration for running the full test suite may vary depending on your machine, but on a modern laptop it will take up to 8 hours and use up to 3GB of RAM"

