Strip Interface class of most of its logic, make it all about Module exports

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 902c43c1330e4c7af7f977c9a41e6d7a8733bc80..a17100d328e57974557e059f2eac812958c412ef 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -11566,11 +11566,6 @@ void HOptimizedGraphBuilder::VisitModuleLiteral(ModuleLiteral* module) {
 }
 
 
-void HOptimizedGraphBuilder::VisitModuleVariable(ModuleVariable* module) {
-  UNREACHABLE();
-}
-
-
 void HOptimizedGraphBuilder::VisitModulePath(ModulePath* module) {
   UNREACHABLE();
 }