Some more instrumentation to narrow down Failure leaks.

src/heap-inl.h

Index: src/heap-inl.h
diff --git a/src/heap-inl.h b/src/heap-inl.h
index deb767e109d3dbb4eea7a61f1505569f0d641a04..cf624fa0e81a621b1889b374ab2bb435d30c4619 100644
--- a/src/heap-inl.h
+++ b/src/heap-inl.h
@@ -132,7 +132,7 @@ MaybeObject* Heap::AllocateInternalSymbol(T t, int chars, uint32_t hash_field) {
 MaybeObject* Heap::AllocateAsciiSymbol(Vector<const char> str,
                                        uint32_t hash_field) {
   if (str.length() > SeqOneByteString::kMaxLength) {
-    return Failure::OutOfMemoryException();
+    return Failure::OutOfMemoryException(0x2);
   }
   // Compute map and object size.
   Map* map = ascii_symbol_map();
@@ -166,7 +166,7 @@ MaybeObject* Heap::AllocateAsciiSymbol(Vector<const char> str,
 MaybeObject* Heap::AllocateTwoByteSymbol(Vector<const uc16> str,
                                          uint32_t hash_field) {
   if (str.length() > SeqTwoByteString::kMaxLength) {
-    return Failure::OutOfMemoryException();
+    return Failure::OutOfMemoryException(0x3);
   }
   // Compute map and object size.
   Map* map = symbol_map();