Add a MathFloor stub generated with TurboFan

src/interface-descriptors.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_CALL_INTERFACE_DESCRIPTOR_H_
 #define V8_CALL_INTERFACE_DESCRIPTOR_H_
 
 #include "src/assembler.h"
 #include "src/macro-assembler.h"
 
@@ skipping 40 matching lines @@
   V(Named)                                    \
   V(CallHandler)                              \
   V(ArgumentAdaptor)                          \
   V(ApiFunction)                              \
   V(ApiAccessor)                              \
   V(ApiGetter)                                \
   V(ArgumentsAccessRead)                      \
   V(StoreArrayLiteralElement)                 \
   V(MathPowTagged)                            \
   V(MathPowInteger)                           \
+  V(MathRoundVariant)                         \
   V(ContextOnly)                              \
   V(GrowArrayElements)
 
 
 class CallInterfaceDescriptorData {
  public:
   CallInterfaceDescriptorData() : register_param_count_(-1) {}
 
   // A copy of the passed in registers and param_representations is made
   // and owned by the CallInterfaceDescriptorData.
@@ skipping 450 matching lines @@
 
 
 class MathPowIntegerDescriptor : public CallInterfaceDescriptor {
  public:
   DECLARE_DESCRIPTOR(MathPowIntegerDescriptor, CallInterfaceDescriptor)
 
   static const Register exponent();
 };
 
 
+class MathRoundVariantDescriptor : public CallInterfaceDescriptor {
+ public:
+  DECLARE_DESCRIPTOR(MathRoundVariantDescriptor, CallInterfaceDescriptor)
+};
+
+
 class ContextOnlyDescriptor : public CallInterfaceDescriptor {
  public:
   DECLARE_DESCRIPTOR(ContextOnlyDescriptor, CallInterfaceDescriptor)
 };
 
 
 class GrowArrayElementsDescriptor : public CallInterfaceDescriptor {
  public:
   DECLARE_DESCRIPTOR(GrowArrayElementsDescriptor, CallInterfaceDescriptor)
 
@@ skipping 16 matching lines @@
 }  // namespace v8::internal
 
 
 #if V8_TARGET_ARCH_ARM64
 #include "src/arm64/interface-descriptors-arm64.h"
 #elif V8_TARGET_ARCH_ARM
 #include "src/arm/interface-descriptors-arm.h"
 #endif
 
 #endif  // V8_CALL_INTERFACE_DESCRIPTOR_H_