//tensorflow/python/distribute:cross_device_ops_test_2gpu is flaky
@rishikasinha-tf flaky test Thanks. This is a known issue due to portpicker cannot always guarantee getting a fresh, unused port for the tests. We don't really have a good strategy to deal with this problem at the moment, other than retrying the test. Any suggestions and/or contribution is highly welcomed. @rainwoodman If there was a way that the build/test process could start a singleton process with portpicker as a server that should resolve the problems with it not being thread safe but I am not a bazel expert and do not know if or how that could be achieved. Each usage of portpicker in a test would then call out to the singleton process with the server and hopefully get a unique port allocation.
Alternatively or additionally making the code that establishes a network connection to be more robust so that it can detect and retry when it fails due to a port conflict.
<details><summary>Click to expand!</summary> 
 
 ### Issue Type

Bug

### Have you reproduced the bug with TF nightly?

Yes

### Source

source

### Tensorflow Version

git HEAD

### Custom Code

No

### OS Platform and Distribution

Ubuntu 20.04

### Mobile device

n/a

### Python version

3.9.16

### Bazel version

6.1.0

### GCC/Compiler version

10.2.1

### CUDA/cuDNN version

n/a

### GPU model and memory

n/a

### Current Behaviour?

//tensorflow/python/distribute:cross_device_ops_test_2gpu fails or timeouts sometimes

x86 log
https://source.cloud.google.com/results/invocations/3008a6bc-b49f-4776-871c-1c5ae046a470/log

AARCH64 log
https://github.com/tensorflow/tensorflow/actions/runs/5379162649/jobs/9759994992#step:5:9913

### Standalone code to reproduce the issue

```shell
bazel --bazelrc=/usertools/cpu.bazelrc test --config=pycpp --config=build_event_export --remote_cache=https://storage.googleapis.com/tensorflow-devinfra-bazel-cache/norbe --google_default_credentials
```


### Relevant log output

```shell
[ RUN      ] CollectiveOpsTest.testBatchReduceDense_test_implementation_CommunicationImplementationRING_numprocesses_2_preferuniqueinstancekey_False_reduceop_ReduceOpSUM_requiredgpus_0
[worker-0]:    W0628 09:23:51.698908 140256382134080 context.py:881] Enabling collective ops after program startup may cause error when accessing previously created tensors.
I0628 09:23:51.700115 139955121788736 multi_process_runner.py:989] Waiting for the result from worker-0
I0628 09:23:51.702625 139955121788736 multi_process_runner.py:989] Waiting for the result from worker-0
I0628 09:23:51.702917 139955121788736 multi_process_runner.py:989] Waiting for the result from worker-1
I0628 09:23:51.711031 139955121788736 multi_process_runner.py:989] Waiting for the result from worker-0
[worker-0]:    2023-06-28 09:23:51.734731: I tensorflow/core/distributed_runtime/rpc/grpc_server_lib.cc:457] Started server with target: grpc://localhost:38213
[worker-1]:    E0628 09:23:51.740952892 1194361 server_chttp2.cc:40]        {"created":"@1687944231.740904797","description":"No address added out of total 1 resolved","file":"external/com_github_grpc_grpc/src/core/ext/transport/chttp2/server/chttp2_server.cc","file_line":395,"referenced_errors":[{"created":"@1687944231.740902919","description":"Failed to add any wildcard listeners","file":"external/com_github_grpc_grpc/src/core/lib/iomgr/tcp_server_posix.cc","file_line":342,"referenced_errors":[{"created":"@1687944231.740878363","description":"Address family not supported by protocol","errno":97,"file":"external/com_github_grpc_grpc/src/core/lib/iomgr/socket_utils_common_posix.cc","file_line":420,"os_error":"Address family not supported by protocol","syscall":"socket","target_address":"[::]:36443"},{"created":"@1687944231.740901905","description":"Unable to configure socket","fd":9,"file":"external/com_github_grpc_grpc/src/core/lib/iomgr/tcp_server_utils_posix_common.cc","file_line":216,"referenced_errors":[{"created":"@1687944231.740897648","description":"Address already in use","errno":98,"file":"external/com_github_grpc_grpc/src/core/lib/iomgr/tcp_server_utils_posix_common.cc","file_line":189,"os_error":"Address already in use","syscall":"bind"}]}]}]}
[worker-1]:    2023-06-28 09:23:51.741121: E tensorflow/core/distributed_runtime/rpc/grpc_server_lib.cc:608] UNKNOWN: Could not start gRPC server
[worker-1]:    2023-06-28 09:23:51.741306: E tensorflow/core/common_runtime/eager/context_distributed_manager.cc:703] Could not start gRPC server
-- Test timed out at 2023-06-28 09:28:39 UTC --
```
</details>