alias_method is private on Ruby 2.3 and 2.4 #148

Job	Run time
ruby-versions / Generate Ruby versions	5s
ubuntu-20.04 2.3	1m 33s
ubuntu-20.04 2.4	1m 9s
ubuntu-20.04 2.5	1m 24s
ubuntu-20.04 2.6	1m 23s
ubuntu-20.04 2.7	1m 35s
ubuntu-20.04 3.0	40s
ubuntu-20.04 3.1	37s
ubuntu-20.04 3.2	29s
ubuntu-20.04 head	34s
ubuntu-20.04 jruby	1m 36s
ubuntu-20.04 jruby-head	1m 43s
ubuntu-20.04 truffleruby	1m 15s
ubuntu-20.04 truffleruby-head	1m 17s
ubuntu-22.04 2.3	1m 26s
ubuntu-22.04 2.4	1m 16s
ubuntu-22.04 2.5	1m 25s
ubuntu-22.04 2.6	1m 28s
ubuntu-22.04 2.7	1m 42s
ubuntu-22.04 3.0	25s
ubuntu-22.04 3.1	43s
ubuntu-22.04 3.2	29s
ubuntu-22.04 head	25s
ubuntu-22.04 jruby	2m 11s
ubuntu-22.04 jruby-head	1m 24s
ubuntu-22.04 truffleruby	1m 2s
ubuntu-22.04 truffleruby-head	1m 35s
macos-11 2.3	2m 28s
macos-11 2.4	2m 25s
macos-11 2.5	2m 24s
macos-11 2.6	2m 28s
macos-11 2.7	2m 26s
macos-11 3.0	38s
macos-11 3.1	41s
macos-11 3.2	40s
macos-11 head	36s
macos-11 jruby	1m 29s
macos-11 jruby-head	1m 28s
macos-11 truffleruby	1m 37s
macos-11 truffleruby-head	1m 44s
macos-12 2.3	2m 15s
macos-12 2.4	2m 9s
macos-12 2.5	2m 9s
macos-12 2.6	2m 10s
macos-12 2.7	2m 3s
macos-12 3.0	42s
macos-12 3.1	38s
macos-12 3.2	40s
macos-12 head	39s
macos-12 jruby	4m 13s
macos-12 jruby-head	1m 20s
macos-12 truffleruby	1m 37s
macos-12 truffleruby-head	1m 33s
windows-latest 2.3	2m 37s
windows-latest 2.4	3m 5s
windows-latest 2.5	4m 32s
windows-latest 2.6	4m 25s
windows-latest 2.7	3m 35s
windows-latest 3.0	2m 9s
windows-latest 3.1	2m 4s
windows-latest 3.2	2m 29s
windows-latest head	1m 59s
ubuntu-latest jruby-9.1	2m 7s
ubuntu-latest jruby-9.2	2m 15s
ubuntu-latest jruby-9.3	1m 38s
	1h 46m 58s

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