Introduce short external strings without pointer cache.

src/objects-printer.cc

Index: src/objects-printer.cc
diff --git a/src/objects-printer.cc b/src/objects-printer.cc
index c9f3f842dff455516bdf53a09da306dd876e0dca..4b5d049f51b039d56f8ccf837b9ff19487ee58bd 100644
--- a/src/objects-printer.cc
+++ b/src/objects-printer.cc
@@ -446,6 +446,9 @@ static const char* TypeToString(InstanceType type) {
     case EXTERNAL_ASCII_SYMBOL_TYPE:
     case EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE:
     case EXTERNAL_SYMBOL_TYPE: return "EXTERNAL_SYMBOL";
+    case SHORT_EXTERNAL_ASCII_SYMBOL_TYPE:
+    case SHORT_EXTERNAL_SYMBOL_WITH_ASCII_DATA_TYPE:
+    case SHORT_EXTERNAL_SYMBOL_TYPE: return "SHORT_EXTERNAL_SYMBOL";
     case ASCII_STRING_TYPE: return "ASCII_STRING";
     case STRING_TYPE: return "TWO_BYTE_STRING";
     case CONS_STRING_TYPE:
@@ -453,6 +456,9 @@ static const char* TypeToString(InstanceType type) {
     case EXTERNAL_ASCII_STRING_TYPE:
     case EXTERNAL_STRING_WITH_ASCII_DATA_TYPE:
     case EXTERNAL_STRING_TYPE: return "EXTERNAL_STRING";
+    case SHORT_EXTERNAL_ASCII_STRING_TYPE:
+    case SHORT_EXTERNAL_STRING_WITH_ASCII_DATA_TYPE:
+    case SHORT_EXTERNAL_STRING_TYPE: return "SHORT_EXTERNAL_STRING";
     case FIXED_ARRAY_TYPE: return "FIXED_ARRAY";
     case BYTE_ARRAY_TYPE: return "BYTE_ARRAY";
     case FREE_SPACE_TYPE: return "FREE_SPACE";