feat: add sourceType: commonjs option

[ota-meshi]

close #1376

I think it's still under discussion how to design the option, but I tried implementing it.
I think the test cases included in this PR will be useful for discussion.

[marijnh]

I don't think we should go against the ESTree spec on what Program.sourceType can hold. I think setting that to "script" when the option is set to "commonjs" makes more sense.

[ota-meshi]

Thank you for checking this PR! I changed Program.sourceType to script when option is commonjs.

[RReverser]

This looks pretty good to me. The only other thing that comes to mind is it might be worth running all the sourceType: "script" tests in CommonJS mode as well, as for most of them it should be true.

[ota-meshi]

Thank you for checking this PR!
I modified test/run.js to run all the sourceType: "script" tests and the same commonjs tests.
e610dd2
(Please let me know if this method should be avoided.)

After adding tests, I noticed that when using commonjs with allowAwaitOutsideFunction, the top-level await couldn't be parsed, so I fixed that.
But maybe allowAwaitOutsideFunction should be ignored for commonjs. What do you think about this?

[marijnh]

But maybe allowAwaitOutsideFunction should be ignored for commonjs. What do you think about this?

It might be reasonable to raise an error when allowAwaitOutsideFunction is set to true with moduleType: "commonjs". Silently ignoring it when it is explicitly set seems too confusing.

[ota-meshi]

Thank you for the comment! I changed it to reject the combination of allowAwaitOutsideFunction and moduleType: "commonjs".

[marijnh]

Thanks, this looks good now.

[JLHwung]

Should we also throw if allowReturnOutsideFunction: false is used with sourceType: "commonjs"?