EXTERNAL_STRING_TYPE 4432 src/heap.cc        case EXTERNAL_STRING_TYPE: return external_symbol_map();
EXTERNAL_STRING_TYPE  491 src/objects-printer.cc     case EXTERNAL_STRING_TYPE: return "EXTERNAL_STRING";
EXTERNAL_STRING_TYPE  233 src/objects.h    V(EXTERNAL_STRING_TYPE)                                                      \
EXTERNAL_STRING_TYPE  380 src/objects.h    V(EXTERNAL_STRING_TYPE,                                                      \