[Merged by Bors] - Migrate to uber gomock #14622

Job	Run time
filter-changes	6s
quicktests	1m 39s
lint	6m 54s
unittests (ubuntu-latest)	8m 14s
unittests (macos-latest)	8m 15s
unittests (self-hosted, macos, arm64)	1s
build (ubuntu-latest)	2m 47s
build (self-hosted, linux, arm64)	23s
build (macos-latest)	3m 51s
build (self-hosted, macos, arm64)	1s
build (windows-latest)	7m 51s
unittests-slower (self-hosted, linux, arm64)	7m 9s
unittests-slower (windows-latest)	7m 58s
ci-status	4s
	55m 13s

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