Fix model int8 quant fail, test=develop (#22891)

As model fails when enable int8 quant, so disable allocate memory in cpu
for small variable.

paddle/fluid/pybind/tensor_py.h

@@ -187,21 +187,12 @@ void SetTensorFromPyArrayT(
     }
   } else {
 #ifdef PADDLE_WITH_CUDA
-    T *dst;
+    auto dst = self->mutable_data<T>(place);
-    if (array.nbytes() <= 4 && !paddle::platform::is_cuda_pinned_place(place)) {
-      dst = self->mutable_data<T>(platform::CPUPlace());
-    } else {
-      dst = self->mutable_data<T>(place);
-    }
     if (paddle::platform::is_cuda_pinned_place(place)) {
       std::memcpy(dst, array.data(), array.nbytes());
     } else if (paddle::platform::is_gpu_place(place)) {
-      if (array.nbytes() <= 4) {
+      paddle::platform::GpuMemcpySync(dst, array.data(), array.nbytes(),
-        std::memcpy(dst, array.data(), array.nbytes());
+                                      cudaMemcpyHostToDevice);
-      } else {
-        paddle::platform::GpuMemcpySync(dst, array.data(), array.nbytes(),
-                                        cudaMemcpyHostToDevice);
-      }
     } else {
       PADDLE_THROW(
           "Incompatible place type: Tensor.set() supports CPUPlace, CUDAPlace "