Bugfix in process handle: Do detaching from owner process separately from derefing.

src/vm/process.cc

Index: src/vm/process.cc
diff --git a/src/vm/process.cc b/src/vm/process.cc
index a7037e2b844d02f5cf3ffa05ab94a7736de0d89d..547bb395aea7eeaa8388ea3a08a320433a2aebbc 100644
--- a/src/vm/process.cc
+++ b/src/vm/process.cc
@@ -109,6 +109,8 @@ Process::~Process() {
   // conditions here.
   ASSERT(ports_ == NULL);
 
+  ProcessHandle::DecrementRef(process_handle_);
+
 #ifdef FLETCH_ENABLE_MULTIPLE_PROCESS_HEAPS
   heap_.ProcessWeakPointers();
 #endif  // #ifdef FLETCH_ENABLE_MULTIPLE_PROCESS_HEAPS
@@ -130,7 +132,7 @@ void Process::Cleanup(Signal::Kind kind) {
 
   // We are going down at this point. If anything else is starting to
   // link/monitor with this [ProcessHandle], it will fail after this line.
-  ProcessHandle::OwnerProcessTerminating(process_handle_);
+  process_handle_->OwnerProcessTerminating();
 
   // Since nobody can send us messages (or signals) at this point, we can
   // propagate the exit signal.