Add specs for Process::Status#>> #1813

Job	Run time
RuboCop	31s
specs (ubuntu, 3.0.6)	1m 31s
specs (ubuntu, 3.1.4)	1m 33s
specs (ubuntu, 3.2.2)	1m 24s
specs (ubuntu, 3.3.0)	1m 21s
specs (macos, 3.0.6)	1m 41s
specs (macos, 3.1.4)	1m 48s
specs (macos, 3.2.2)	1m 17s
specs (macos, 3.3.0)	1m 35s
specs (windows, 3.0.6)	3m 16s
specs (windows, 3.1.4)	4m 11s
specs (windows, 3.2.2)	4m 40s
specs (windows, 3.3.0)	3m 23s
specs (ubuntu, 3.3.0, --enable-frozen-string-literal)	1m 25s
	29m 36s

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