The hard part of parsing them in import statements and calls was already
done so this is just removing some check which threw before on
assertions. And filtering the assertions based on the result of a new
host hook.
Because we can have arbitrary in- and export names with strings we can
have '*' and '' which means using '*' as an indicating namespace imports
failed / behaved incorrectly for string imports '*'.
We now use more specific types to indicate these special states instead
of these 'magic' string values.
Do note that 'default' is not actually a magic string value but one
specified by the spec. And you can in fact export the default value by
doing: `export { 1 as default }`.
