message: [TF:TRT] Refine FloorDiv for TensorRT 6+.
  Previously we emulate a FloorDiv in TensorRT by doing a Div and then a Floor.
  TensorRT actually has a native FloorDiv, and this change replace the emulation
  with the native implementation for TensorRT 6+.
diff: @@ -4348,8 +4348,11 @@ BinaryOperationMap() {
  {"Mul", nvinfer1::ElementWiseOperation::kPROD},
  {"Sub", nvinfer1::ElementWiseOperation::kSUB},
  {"Div", nvinfer1::ElementWiseOperation::kDIV},
  -#if IS_TRT_VERSION_GE(5, 1, 0, 0)
  - // This op applies Floor after Div.
  +#if IS_TRT_VERSION_GE(6, 0, 1, 0)
  + // Use TensorRT native FloorDiv.
  + {"FloorDiv", nvinfer1::ElementWiseOperation::kFLOOR_DIV},
  +#elif IS_TRT_VERSION_GE(5, 1, 0, 0)
  + // Emulate FloorDiv by doing Div then Floor.
  {"FloorDiv", nvinfer1::ElementWiseOperation::kDIV},
  #endif
  {"RealDiv", nvinfer1::ElementWiseOperation::kDIV},
  @@ -4414,7 +4417,7 @@ Status ConvertBinary(OpConverterParams* params) {
  SetLayerName(layer, node_def);
  nvinfer1::ITensor* trt_tensor = layer->getOutput(0);
  -#if IS_TRT_VERSION_GE(5, 1, 0, 0)
  +#if IS_TRT_VERSION_GE(5, 1, 0, 0) and !IS_TRT_VERSION_GE(6, 0, 1, 0)
  if (node_def.op() == "FloorDiv") {
  layer = params->converter->network()->addUnary(
  *trt_tensor, nvinfer1::UnaryOperation::kFLOOR);
  