Bug 1542355 - Fixes CACHEIR_LOGS=1 crashing nightly build. r=mgaudet

Differential Revision: https://phabricator.services.mozilla.com/D26987

--HG--
extra : moz-landing-system : lando

js/src/vm/JSObject.cpp

@@ -132,6 +132,7 @@ JS_PUBLIC_API const char* JS::InformalValueTypeName(const Value& v) {
     case ValueType::Object:
       return v.toObject().getClass()->name;
     case ValueType::Magic:
+      return "magic";
     case ValueType::PrivateGCThing:
       break;
   }