Add a MathFloor stub generated with TurboFan

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index 2ad1ff447e26d51a7b4750ab979e8a9b96d0a1bb..f5d65f455cd6b77e819f9fda3b0f842e3f1001b7 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -175,6 +175,14 @@ int CompilationInfo::num_parameters() const {
 }
 
 
+int CompilationInfo::num_parameters_including_this() const {
+  return num_parameters() + (is_this_defined() ? 1 : 0);
+}
+
+
+bool CompilationInfo::is_this_defined() const { return !IsStub(); }
+
+
 int CompilationInfo::num_heap_slots() const {
   return has_scope() ? scope()->num_heap_slots() : 0;
 }