Add dynamic stack frame alignment to optimized functions with untagged doubles on the stack.

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index dcfde2ebb2675294bed69c3925320dcbdb28826a..8f97fe32c10b303701f0259a520e16e7d8567de9 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -596,6 +596,9 @@ class ExternalReference BASE_EMBEDDED {
   // Static variable Factory::arguments_marker.location()
   static ExternalReference arguments_marker_location(Isolate* isolate);
 
+  // Static variable Factory::frame_alignment_marker.location()
+  static ExternalReference frame_alignment_marker_location(Isolate* isolate);
+
   // Static variable Heap::roots_address()
   static ExternalReference roots_address(Isolate* isolate);