Fix incorrect coercion of other failures to Failure::Exception in ReThrow.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index e68ac531f7bd320862ce24a89781df567332b7c0..b922c087426cc97af54588db79be80c16f9f2d67 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -628,6 +628,7 @@ struct ValueInfo : public Malloced {
 // A template-ized version of the IsXXX functions.
 template <class C> static inline bool Is(Object* obj);
 
+class Failure;
 
 class MaybeObject BASE_EMBEDDED {
  public:
@@ -641,6 +642,10 @@ class MaybeObject BASE_EMBEDDED {
     *obj = reinterpret_cast<Object*>(this);
     return true;
   }
+  inline Failure* ToFailureUnchecked() {
+    ASSERT(IsFailure());
+    return reinterpret_cast<Failure*>(this);
+  }
   inline Object* ToObjectUnchecked() {
     ASSERT(!IsFailure());
     return reinterpret_cast<Object*>(this);