Add support for javascript incompatibility warnings.

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 35921)
+++ runtime/vm/object.h	(working copy)
@@ -4013,6 +4013,7 @@
     kError,
     kMalformedType,
     kMalboundedType,
+    kBailout,
   };
 
   Kind kind() const { return static_cast<Kind>(raw_ptr()->kind_); }
@@ -4041,6 +4042,7 @@
                                          const char* format, va_list args);
 
   static RawLanguageError* New(const String& formatted_message,
+                               Kind kind = kError,
                                Heap::Space space = Heap::kNew);
 
   virtual const char* ToErrorCString() const;