Add a MathFloor stub generated with TurboFan

src/compiler/linkage.cc

Index: src/compiler/linkage.cc
diff --git a/src/compiler/linkage.cc b/src/compiler/linkage.cc
index 2f22d9a6be5c3a6efdbd1c9e439a2d0e0387ad3f..faba7b0870ec1751b069712ff944b60a8bcef9c9 100644
--- a/src/compiler/linkage.cc
+++ b/src/compiler/linkage.cc
@@ -51,11 +51,11 @@ bool CallDescriptor::HasSameReturnLocationsAs(
 CallDescriptor* Linkage::ComputeIncoming(Zone* zone, CompilationInfo* info) {
   if (info->code_stub() != NULL) {
     // Use the code stub interface descriptor.
-    CallInterfaceDescriptor descriptor =
-        info->code_stub()->GetCallInterfaceDescriptor();
-    return GetStubCallDescriptor(info->isolate(), zone, descriptor, 0,
-                                 CallDescriptor::kNoFlags,
-                                 Operator::kNoProperties);
+    CodeStub* stub = info->code_stub();
+    CallInterfaceDescriptor descriptor = stub->GetCallInterfaceDescriptor();
+    return GetStubCallDescriptor(
+        info->isolate(), zone, descriptor, stub->GetStackParameterCount(),
+        CallDescriptor::kNoFlags, Operator::kNoProperties);
   }
   if (info->function() != NULL) {
     // If we already have the function literal, use the number of parameters