feat(compat): add .code to dyn import error

[kt3k]

part of #12577, closes #12588

This PR changes the error class for dynamic import rejection in compat mode. Some tools (e.g. mocha) uses .code property of error object to detect the resolution failure of dynamic import (ref: https://github.com/mochajs/mocha/blob/97b84708afb42e552cb906a54f9f2aa2e6a98ba4/lib/nodejs/esm-utils.js#L47-L56 ). This change simulates the above behavior in compat mode.

This change enables compat mode to run the basic feature of mocha cli

[kt3k]

cli/tests/testdata/fix_dynamic_import_errors.js test case strangely panicks at the 2nd dynamic import..

[kt3k]

Now ready for review

I first tried to reuse class_name of CustomError for accessing the custom js error constructor, but that didn't work because some errors cause panic during getting error class (caused by cli/tests/testdata/fix_dynamic_import_errors.js). Now I created a dedicated error class for that purpose CustomErrorWithJsConstructor and retrieves js constructor name from that class during rejections of dynamic imports

[bartlomieju]

Please discuss this change in the design letting before landing.

[lucacasonato]

I am not in favor of this Deno.compat.errors namespace. In node await import("xxxxxx") throws a regular Error (no subclass), with a .code on it. In the browser it throws a TypeError. I think we should always throw a TypeError (also in non-compat mode), and in compat mode add a code property to that.

[lucacasonato]

LGTM