Move IO configuration to IRB::Irb (#681) #2380

Job	Run time
ruby-versions / Generate Ruby versions	2s
vterm-yamatanooroti 2.7 (latest reline)	1m 12s
vterm-yamatanooroti 2.7	1m 26s
vterm-yamatanooroti 3.0 (latest reline)	45s
vterm-yamatanooroti 3.0	44s
vterm-yamatanooroti 3.1 (latest reline)	47s
vterm-yamatanooroti 3.1	1m 5s
vterm-yamatanooroti 3.2 (latest reline)	44s
vterm-yamatanooroti 3.2	1m 14s
vterm-yamatanooroti head (latest reline)	1m 24s
vterm-yamatanooroti head	50s
rake test 2.7 (latest reline)	1m 3s
rake test 2.7	59s
rake test 3.0 (latest reline)	34s
rake test 3.0	39s
rake test 3.1 (latest reline)	32s
rake test 3.1	32s
rake test 3.2 (latest reline)	37s
rake test 3.2	30s
rake test head (latest reline)	29s
rake test head	38s
rake test truffleruby-head (latest reline)	6m 51s
rake test truffleruby-head	7m 43s
	31m 20s

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