Add test ensuring local gem downloads overwrite stale cache #7671

Job	Run time
Rubygems on Ubuntu (3.4)	4m 11s
Rubygems on Ubuntu (jruby)	7m 50s
Rubygems on Ubuntu (3.3)	1m 57s
Rubygems on macOS (3.3)	1m 48s
Rubygems on Windows (3.4)	3m 46s
Rubygems on Ubuntu (truffleruby)	3m 45s
Rubygems on macOS (3.2)	2m 49s
Rubygems on Windows (3.3)	3m 40s
Rubygems on Ubuntu (3.2)	2m 1s
Rubygems on macOS (3.4)	3m 32s
Rubygems on Windows (3.2)	4m 30s
All rubygems jobs pass	5s
	39m 54s

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