[Precision Depth Alignment] paddle.sin and paddle.cos aligns with torch precision. (PaddlePaddle#75503)

* accuracy_stable_sin

* accuracy_stable_cos

Author: zhengshengning

paddle/phi/kernels/funcs/activation_functor.h

@@ -3500,7 +3500,11 @@ struct CudaCosGradFunctor : public BaseActivationFunctor<T> {
                                           const T arg_x) const {
     MPType dout = static_cast<MPType>(arg_dout);
     MPType x = static_cast<MPType>(arg_x);
-    return static_cast<T>(-dout * sin(x));
+    if constexpr (std::is_same<T, phi::float16>::value) {
+      return static_cast<T>(-arg_dout * static_cast<T>(sin(x)));
+    } else {
+      return static_cast<T>(-dout * sin(x));
+    }
   }
 
   static constexpr ActBwdOpFwdDeps FwdDeps() { return ActBwdOpFwdDeps::kDepX; }
@@ -3835,7 +3839,11 @@ struct CudaSinGradFunctor : public BaseActivationFunctor<T> {
                                           const T arg_x) const {
     MPType dout = static_cast<MPType>(arg_dout);
     MPType x = static_cast<MPType>(arg_x);
-    return static_cast<T>(dout * cos(x));
+    if constexpr (std::is_same<T, phi::float16>::value) {
+      return static_cast<T>(arg_dout * static_cast<T>(cos(x)));
+    } else {
+      return static_cast<T>(dout * cos(x));
+    }
   }
 
   static constexpr ActBwdOpFwdDeps FwdDeps() { return ActBwdOpFwdDeps::kDepX; }