Refine test code related unsupported Ruby version #334

Job	Run time
ruby-versions / Generate Ruby versions	1s
ubuntu-latest 2.7	53s
ubuntu-latest 3.0	28s
ubuntu-latest 3.1	27s
ubuntu-latest 3.2	31s
ubuntu-latest 3.3	25s
ubuntu-latest debug	41s
ubuntu-latest head	35s
macos-11 2.7	1m 57s
macos-11 3.0	48s
macos-11 3.1	56s
macos-11 3.2	1m 0s
macos-11 3.3	53s
macos-11 debug	1m 8s
macos-11 head	47s
windows-latest 2.7	3m 45s
windows-latest 3.0	2m 20s
windows-latest 3.1	2m 58s
windows-latest 3.2	3m 2s
windows-latest 3.3	4m 8s
windows-latest head	3m 1s
windows-latest mingw	2m 18s
windows-latest mswin	2m 31s
	35m 33s

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