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

src/parser.h

Index: src/parser.h
diff --git a/src/parser.h b/src/parser.h
index 745d950256354d6d0835197d4664a1e6fe3c3c6e..a003c4ab42c6326b7c95e64f77cadd52114248ff 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -795,9 +795,7 @@ class Parser : public ParserBase<ParserTraits> {
   void CheckConflictingVarDeclarations(Scope* scope, bool* ok);
 
   // Parser support
-  VariableProxy* NewUnresolved(const AstRawString* name,
-                               VariableMode mode,
-                               Interface* interface);
+  VariableProxy* NewUnresolved(const AstRawString* name, VariableMode mode);
   void Declare(Declaration* declaration, bool resolve, bool* ok);
 
   bool TargetStackContainsLabel(const AstRawString* label);