Fix CROSS_COMPILING guard and RUBYOPT=-v spec #1771

Job	Run time
RuboCop	31s
specs (ubuntu, 3.0.6)	1m 37s
specs (ubuntu, 3.1.4)	1m 33s
specs (ubuntu, 3.2.2)	1m 32s
specs (ubuntu, 3.3.0)	1m 30s
specs (macos, 3.0.6)	1m 26s
specs (macos, 3.1.4)	1m 20s
specs (macos, 3.2.2)	1m 9s
specs (macos, 3.3.0)	1m 9s
specs (windows, 3.0.6)	5m 38s
specs (windows, 3.1.4)	5m 45s
specs (windows, 3.2.2)	5m 46s
specs (windows, 3.3.0)	3m 53s
specs (ubuntu, 3.3.0, --enable-frozen-string-literal)	1m 27s
	34m 16s

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