Add basic API support for Map & Set

src/contexts.h

Index: src/contexts.h
diff --git a/src/contexts.h b/src/contexts.h
index b692fd9c2210f7b65524462b4297feabd5c20e48..b1461f7cd87dd6d930851acc3eb813ebe52a5476 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -184,6 +184,8 @@ enum BindingFlags {
   V(STRONG_GENERATOR_FUNCTION_MAP_INDEX, Map, strong_generator_function_map)   \
   V(GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX, Map, generator_object_prototype_map) \
   V(ITERATOR_RESULT_MAP_INDEX, Map, iterator_result_map)                       \
+  V(JS_MAP_MAP_INDEX, Map, js_map_map)                                         \
+  V(JS_SET_MAP_INDEX, Map, js_set_map)                                         \
   V(MAP_ITERATOR_MAP_INDEX, Map, map_iterator_map)                             \
   V(SET_ITERATOR_MAP_INDEX, Map, set_iterator_map)                             \
   V(ARRAY_VALUES_ITERATOR_INDEX, JSFunction, array_values_iterator)            \
@@ -422,6 +424,8 @@ class Context: public FixedArray {
     STRONG_GENERATOR_FUNCTION_MAP_INDEX,
     GENERATOR_OBJECT_PROTOTYPE_MAP_INDEX,
     ITERATOR_RESULT_MAP_INDEX,
+    JS_MAP_MAP_INDEX,
+    JS_SET_MAP_INDEX,
     MAP_ITERATOR_MAP_INDEX,
     SET_ITERATOR_MAP_INDEX,
     ARRAY_VALUES_ITERATOR_INDEX,