[release 0.21] remove prototype stuff #3745

Job	Run time
unittests-extended	0s
onnx / linux-job	55s
unittests-linux (3.11, linux.12xlarge, cpu) / linux-job	47s
unittests-linux (3.10, linux.12xlarge, cpu) / linux-job	57s
unittests-linux (3.12, linux.12xlarge, cpu) / linux-job	48s
unittests-linux (3.9, linux.12xlarge, cpu) / linux-job	45s
unittests-linux (3.9, linux.g5.4xlarge.nvidia.gpu, cuda, 11.8) / linux-job	57s
unittests-macos (3.10, macos-m1-stable) / macos-job	1m 23s
unittests-macos (3.11, macos-m1-stable) / macos-job	1m 8s
unittests-macos (3.12, macos-m1-stable) / macos-job	1m 23s
unittests-macos (3.9, macos-m1-stable) / macos-job	1m 9s
unittests-windows (3.10, windows.4xlarge, cpu) / windows-job	2m 5s
unittests-windows (3.11, windows.4xlarge, cpu) / windows-job	4m 25s
unittests-windows (3.12, windows.4xlarge, cpu) / windows-job	1m 30s
unittests-windows (3.9, windows.4xlarge, cpu) / windows-job	5m 53s
unittests-windows (3.9, windows.g5.4xlarge.nvidia.gpu, cuda, 11.8) / windows-job	43s
	24m 48s

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