Tests

Use Chocolatey to install bzip2.dll for Windows tests in CI. #27

Job	Run time
test (ubuntu, 3.1)	12s
test (ubuntu, 3.2)	14s
test (ubuntu, jruby-head)	1m 6s
test (ubuntu, 3.0)	17s
test (ubuntu, 3.3)	24s
test (ubuntu, truffleruby)	26s
test (windows, 3.0)	1m 1s
test (ubuntu, 3.4)	25s
test (ubuntu, jruby)	1m 2s
test (ubuntu, head)	11s
test (macos, 3.0)	26s
test (ubuntu, truffleruby-head)	28s
finish	3s
	6m 15s

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