refactor spec

[devsnek]

• Combines the two dynamic import sections
• Adds a type error guard for what was previously an assertion failure
• Fixes evaluation order of args

[devsnek]

@dandclark ptal

[dandclark]

Thanks @devsnek for this change, just one other issue I noticed. In https://github.com/tc39/proposal-import-assertions/pull/106 we ended up doing a type check on the assertion values, rejecting the promise if any of them are not strings. The is an entry of supportedAssertions check was also moved inside the loop, so that this always rejects regardless of whether maybeSupportedAssertion is a supported assertion:

import("./foo", { assert: { maybeSupportedAssertion: { isAString: false } });

Could you update your change to keep the current behavior of rejecting for non-strings? After that's done I think this is ready to merge. I really like this refactoring.

[dandclark]

Thanks for the change!