Compress deopt instructions in memory using variable length encoding.

runtime/vm/flow_graph_compiler_x64.cc

Index: runtime/vm/flow_graph_compiler_x64.cc
diff --git a/runtime/vm/flow_graph_compiler_x64.cc b/runtime/vm/flow_graph_compiler_x64.cc
index e60c09e4f785421ee33eec83f3fb34070ab3c593..05f880070521e3c241ee0262cf847b08ceb45197 100644
--- a/runtime/vm/flow_graph_compiler_x64.cc
+++ b/runtime/vm/flow_graph_compiler_x64.cc
@@ -78,12 +78,12 @@ void FlowGraphCompiler::ExitIntrinsicMode() {
 }
 
 
-RawDeoptInfo* CompilerDeoptInfo::CreateDeoptInfo(FlowGraphCompiler* compiler,
+RawTypedData* CompilerDeoptInfo::CreateDeoptInfo(FlowGraphCompiler* compiler,
                                                  DeoptInfoBuilder* builder,
                                                  const Array& deopt_table) {
   if (deopt_env_ == NULL) {
     ++builder->current_info_number_;
-    return DeoptInfo::null();
+    return TypedData::null();
   }
 
   intptr_t stack_height = compiler->StackSize();