Use a different map to distinguish eval contexts

src/factory.h

Index: src/factory.h
diff --git a/src/factory.h b/src/factory.h
index 09cb9405be41a69a0247c14b7d1aff4d03c20b95..d35a05f2a8dab0240ca427a64d4e0bcf290da954 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -280,6 +280,11 @@ class V8_EXPORT_PRIVATE Factory final {
                                    Handle<JSFunction> function,
                                    Handle<ScopeInfo> scope_info);
 
+  // Create a eval context.
+  Handle<Context> NewEvalContext(Handle<Module> module,
+                                 Handle<JSFunction> function,
+                                 Handle<ScopeInfo> scope_info);
+
   // Create a function context.
   Handle<Context> NewFunctionContext(int length, Handle<JSFunction> function);