[builtins] Provide Math.floor as TurboFan builtin.

src/crankshaft/hydrogen.cc

Index: src/crankshaft/hydrogen.cc
diff --git a/src/crankshaft/hydrogen.cc b/src/crankshaft/hydrogen.cc
index 5249534adfa05e9ae3cac8543aa547d14973dff7..ae037f351f1d5a4158d6667ad0dfff5fd698a3d1 100644
--- a/src/crankshaft/hydrogen.cc
+++ b/src/crankshaft/hydrogen.cc
@@ -12725,15 +12725,6 @@ void HOptimizedGraphBuilder::GenerateMathClz32(CallRuntime* call) {
 }
 
 
-void HOptimizedGraphBuilder::GenerateMathFloor(CallRuntime* call) {
-  DCHECK(call->arguments()->length() == 1);
-  CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
-  HValue* value = Pop();
-  HInstruction* result = NewUncasted<HUnaryMathOperation>(value, kMathFloor);
-  return ast_context()->ReturnInstruction(result, call->id());
-}
-
-
 void HOptimizedGraphBuilder::GenerateMathLogRT(CallRuntime* call) {
   DCHECK(call->arguments()->length() == 1);
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));