Optimize implementation of Math.floor a little by special casing...

src/jump-target.h

Index: src/jump-target.h
===================================================================
--- src/jump-target.h	(revision 3503)
+++ src/jump-target.h	(working copy)
@@ -112,7 +112,8 @@
 
   // Emit a conditional branch to the target.  There must be a current
   // frame at the branch.  The current frame will fall through to the
-  // code after the branch.
+  // code after the branch.  The arg is a result that is live both at
+  // the target and the fall-through.
   virtual void Branch(Condition cc, Hint hint = no_hint);
   virtual void Branch(Condition cc, Result* arg, Hint hint = no_hint);