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 343da07e89ee319f2738b2d48abbbf8603b57cdb..ff36fe90e0b0cd1c9a5c44f6086b7dc6ba069e33 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -798,9 +798,7 @@ 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);