[Math] implement Math.random as TFJ builtin.

src/contexts.h

Index: src/contexts.h
diff --git a/src/contexts.h b/src/contexts.h
index f03df9471c81c79d71382569ab3ffba7ec47a0a3..f3b1da66e1972c276e9d38851425ad11302729bd 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -185,6 +185,8 @@ enum ContextLookupFlags {
   V(MAP_CACHE_INDEX, Object, map_cache)                                        \
   V(MAP_ITERATOR_MAP_INDEX, Map, map_iterator_map)                             \
   V(STRING_ITERATOR_MAP_INDEX, Map, string_iterator_map)                       \
+  V(MATH_RANDOM_INDEX_INDEX, Smi, math_random_index)                           \
+  V(MATH_RANDOM_CACHE_INDEX, Object, math_random_cache)                        \
   V(MESSAGE_LISTENERS_INDEX, TemplateList, message_listeners)                  \
   V(NATIVES_UTILS_OBJECT_INDEX, Object, natives_utils_object)                  \
   V(NORMALIZED_MAP_CACHE_INDEX, Object, normalized_map_cache)                  \