Add a MathFloor stub generated with TurboFan

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index ff3a86a10c47f2db9d32958bb3debfb4be4671ff..8cbdb0c2b78ea2b83b24a60db5d68affe8f8271f 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -165,6 +165,8 @@ class CompilationInfo {
   Handle<Code> unoptimized_code() const { return unoptimized_code_; }
   int opt_count() const { return opt_count_; }
   int num_parameters() const;
+  int num_parameters_including_this() const;
+  bool is_this_defined() const;
   int num_heap_slots() const;
   Code::Flags flags() const;
   bool has_scope() const { return scope() != nullptr; }
@@ -387,6 +389,8 @@ class CompilationInfo {
 
   bool is_simple_parameter_list();
 
+  Handle<Code> GenerateCodeStub();
+
  protected:
   ParseInfo* parse_info_;