chore(gpu): remove useless syncs

Author: agnesLeroy

backends/tfhe-cuda-backend/cuda/src/integer/integer.cuh

@@ -536,7 +536,6 @@ void generate_device_accumulator_bivariate(
                                          message_modulus, carry_modulus, f);
 
   // copy host lut and lut_indexes_vec to device
-  cuda_synchronize_stream(stream, gpu_index);
   cuda_memcpy_async_to_gpu(acc_bivariate, h_lut,
                            (glwe_dimension + 1) * polynomial_size *
                                sizeof(Torus),
@@ -602,7 +601,6 @@ void generate_device_accumulator(cudaStream_t stream, uint32_t gpu_index,
   generate_lookup_table<Torus>(h_lut, glwe_dimension, polynomial_size,
                                message_modulus, carry_modulus, f);
 
-  cuda_synchronize_stream(stream, gpu_index);
   // copy host lut and lut_indexes_vec to device
   cuda_memcpy_async_to_gpu(
       acc, h_lut, (glwe_dimension + 1) * polynomial_size * sizeof(Torus),