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

src/compiler/ast-graph-builder.cc

Index: src/compiler/ast-graph-builder.cc
diff --git a/src/compiler/ast-graph-builder.cc b/src/compiler/ast-graph-builder.cc
index 89c8339c2a12b1ee3e48538ca7202018c26ee5ff..c33cc60ce573afa4b9270c3f83a8588e3f085421 100644
--- a/src/compiler/ast-graph-builder.cc
+++ b/src/compiler/ast-graph-builder.cc
@@ -876,11 +876,6 @@ void AstGraphBuilder::VisitExportDeclaration(ExportDeclaration* decl) {
 void AstGraphBuilder::VisitModuleLiteral(ModuleLiteral* modl) { UNREACHABLE(); }
 
 
-void AstGraphBuilder::VisitModuleVariable(ModuleVariable* modl) {
-  UNREACHABLE();
-}
-
-
 void AstGraphBuilder::VisitModulePath(ModulePath* modl) { UNREACHABLE(); }