Normative: account for possible abrupt completion

The GetExportedNames method returns an abrupt completion when the host
cannot resolve the requested module. This possibility must be accounted
for when the method invokes itself.

spec.html

@@ -20747,7 +20747,7 @@ <h1>GetExportedNames( _exportStarSet_ ) Concrete Method</h1>
               1. Append _e_.[[ExportName]] to _exportedNames_.
             1. For each ExportEntry Record _e_ in _module_.[[StarExportEntries]], do
               1. Let _requestedModule_ be ? HostResolveImportedModule(_module_, _e_.[[ModuleRequest]]).
-              1. Let _starNames_ be _requestedModule_.GetExportedNames(_exportStarSet_).
+              1. Let _starNames_ be ? _requestedModule_.GetExportedNames(_exportStarSet_).
               1. For each element _n_ of _starNames_, do
                 1. If SameValue(_n_, `"default"`) is *false*, then
                   1. If _n_ is not an element of _exportedNames_, then