Improve error response time

[pea-sys]

Feature request summary
It would be better to check if the output destination is accessible first when the --output-path option is used during the lightHouse run.
The current behavior is that if the --output-path option is used incorrectly, an error is output after all work.

What is the motivation or use case for changing this?
Because it was not a good experience for me.

How is this beneficial to Lighthouse?

• Improved usability
• Prevent unnecessary resource use

[pea-sys]

@connorjclark
thanks