Bug 2002191 - Align indirect and direct module namespace re-exports r=jonco

This patch implements tc39/ecma262#3715, to make

  import * as ns from "mod";
  export { ns };

behave the same as

  export * as ns from "mod";

Tested by tc39/test262#4606

Differential Revision: https://phabricator.services.mozilla.com/D274013

Author: nicolo-ribaudo

js/src/builtin/ModuleObject.cpp

@@ -1698,13 +1698,17 @@ bool ModuleBuilder::buildTables(frontend::StencilModuleMetadata& metadata) {
           return false;
         }
       } else {
+        // All names should have already been marked as used-by-stencil.
         if (!importEntry->importName) {
-          if (!metadata.localExportEntries.append(exp)) {
+          // This is a re-export of an imported module namespace object.
+          auto entry = frontend::StencilModuleEntry::exportNamespaceFromEntry(
+              importEntry->moduleRequest, exp.exportName, exp.lineno,
+              exp.column);
+          if (!metadata.indirectExportEntries.append(entry)) {
             js::ReportOutOfMemory(fc_);
             return false;
           }
         } else {
-          // All names should have already been marked as used-by-stencil.
           auto entry = frontend::StencilModuleEntry::exportFromEntry(
               importEntry->moduleRequest, importEntry->importName,
               exp.exportName, exp.lineno, exp.column);