LiveEdit: implement stack manipulations for x64

src/liveedit.cc

Index: src/liveedit.cc
diff --git a/src/liveedit.cc b/src/liveedit.cc
index 2ac24fba0774ff6817c8f4561cfb8091f9756e77..769ac35c854860ffcc2a7e0af7d967cc3dd92067 100644
--- a/src/liveedit.cc
+++ b/src/liveedit.cc
@@ -1206,7 +1206,7 @@ static const char* DropFrames(Vector<StackFrame*> frames,
                               int bottom_js_frame_index,
                               Debug::FrameDropMode* mode,
                               Object*** restarter_frame_function_pointer) {
-  if (Debug::kFrameDropperFrameSize < 0) {
+  if (!Debug::kFrameDropperSupported) {
     return "Stack manipulations are not supported in this architecture.";
   }