Remove v7r3 tests #1361

Job	Run time
Build installer (linux-64)	5m 33s
Build installer (linux-aarch64)	4m 50s
Build installer (linux-ppc64le)	4m 54s
Build installer (osx-arm64)	3m 40s
Build installer (osx-64)	5m 15s
Create environment.yaml (linux-64)	41s
Basic tests (centos:7)	58s
macOS tests (macos-11)	1m 42s
Basic tests (centos:8)	55s
macOS tests (macos-12)	1m 33s
Integration tests (Py3 server) (rel-v8r0)	20m 57s
Integration tests (Py3 server) (integration)	23m 1s
Show release notes and diff	1m 35s
	1h 15m 34s

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