Disable allocation sinking in the presence of try-catch.

runtime/vm/compiler.cc

Index: runtime/vm/compiler.cc
===================================================================
--- runtime/vm/compiler.cc	(revision 25142)
+++ runtime/vm/compiler.cc	(working copy)
@@ -450,7 +450,9 @@
       // Attempt to sink allocations of temporary non-escaping objects to
       // the deoptimization path.
       AllocationSinking* sinking = NULL;
-      if (FLAG_allocation_sinking) {
+      if (FLAG_allocation_sinking &&
+          (flow_graph->graph_entry()->SuccessorCount()  == 1)) {
+        // TODO(fschneider): Support allocation sinking with try-catch.
         sinking = new AllocationSinking(flow_graph);
         sinking->Optimize();
       }