Filter out synthetic variables from with scopes

src/ast/scopes.h

Index: src/ast/scopes.h
diff --git a/src/ast/scopes.h b/src/ast/scopes.h
index 9bc1013d4d70d24a2f74d25f7fd99675fd396b5f..68cc3a4aada346b8596becd80c4348c4c2c5ce38 100644
--- a/src/ast/scopes.h
+++ b/src/ast/scopes.h
@@ -415,6 +415,12 @@ class Scope: public ZoneObject {
     is_lazily_parsed_ = is_lazily_parsed;
   }
 
+  // Return true if this local was introduced by the compiler, and should not be
+  // exposed to the user in a debugger.
+  // Parallel to ScopeInfo::VariableIsSynthetic, an AstRawString version must
+  // exist so the predicate can be called on un-internalized strings.
+  static bool VariableIsSynthetic(const AstRawString* name);
+
  protected:
   explicit Scope(Zone* zone);