Fix bug in CompilationHandlescope constructor.

This will never be triggered in the state v8 is currently in, but will crash v8 when multiple DeferredHandles are queued up during parallel compilation.

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/10696178

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12050 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/api.h

@@ -399,8 +399,12 @@ class DeferredHandles {
  private:
   DeferredHandles(DeferredHandles* next, Object** first_block_limit,
                   HandleScopeImplementer* impl)
-      : next_(next), previous_(NULL), first_block_limit_(first_block_limit),
-        impl_(impl) {}
+      : next_(next),
+        previous_(NULL),
+        first_block_limit_(first_block_limit),
+        impl_(impl) {
+    if (next != NULL) next->previous_ = this;
+  }
 
   void Iterate(ObjectVisitor* v);