[CUDA] Remove shape warnings in NHWC <> NCHW unit tests (#17992)
There were some warning in https://dev.azure.com/onnxruntime/onnxruntime/_build/results?buildId=1170770
e.g.
```
[ RUN ] CudaNhwcTypedTest/1.AveragePoolNhwcPad @ /home/administrator/onnxruntime/onnxruntime/test/providers/cuda/nhwc/pool_test.cc:84
[W:onnxruntime:Default, graph.cc:108 MergeShapeInfo] Error merging shape info for output. 'Y' source:{1,16,66,66} target:{1,16,67,67}. Falling back to lenient merge.
```
These warnings where not specific to NHWC or NCHW but were just a miscalculation of output shape in some tests.