[heap] Remove obsolete DisallowAllocationFailure scope.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index d60a481c201bd6428d7f1c6efbd713587a2970b5..62005f4e4220564a86a3b97e4aae0e73a42770ca 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -2069,7 +2069,7 @@ bool Isolate::Init(Deserializer* des) {
   }
 
   // The initialization process does not handle memory exhaustion.
-  DisallowAllocationFailure disallow_allocation_failure(this);
+  AlwaysAllocateScope always_allocate(this);
 
   memory_allocator_ = new MemoryAllocator(this);
   code_range_ = new CodeRange(this);