!626 gpu dynamic memory pool can't reuse allReduce in multi-stream

Merge pull request !626 from limingqi107/master

mindspore/ccsrc/device/gpu/gpu_kernel_runtime.cc

@@ -322,6 +322,9 @@ void GPUKernelRuntime::FreeKernelDynamicRes(const mindspore::AnfNodePtr &kernel,
   MS_EXCEPTION_IF_NULL(mem_reuse_util_ptr);
   auto cnode = kernel->cast<CNodePtr>();
   MS_EXCEPTION_IF_NULL(cnode);
+  if (AnfAlgo::GetCNodeName(kernel) == kAllReduceOpName) {
+    return;
+  }
   // Free the input of kernel by reference count.
   for (size_t i = 0; i < AnfAlgo::GetInputTensorNum(kernel); ++i) {
     auto kernel_ref_count_ptr = mem_reuse_util_ptr->GetKernelInputRef(cnode, i);