Improve history test's encoding setting #4036

Job	Run time
lint	9s
Debug compatibility test	5m 43s
ruby-versions / Generate Ruby versions	2s
vterm-yamatanooroti 2.7 (latest reline)	40s
rake test 2.7 (latest reline)	1m 29s
vterm-yamatanooroti 2.7	45s
rake test 2.7	1m 35s
vterm-yamatanooroti 3.0 (latest reline)	28s
rake test 3.0 (latest reline)	1m 29s
vterm-yamatanooroti 3.0	36s
rake test 3.0	1m 25s
vterm-yamatanooroti 3.1 (latest reline)	35s
rake test 3.1 (latest reline)	1m 30s
vterm-yamatanooroti 3.1	34s
vterm-yamatanooroti 3.2 (latest reline)	31s
rake test 3.1	1m 23s
rake test 3.2 (latest reline)	1m 24s
vterm-yamatanooroti 3.2	39s
rake test 3.2	1m 22s
vterm-yamatanooroti 3.3 (latest reline)	29s
rake test 3.3 (latest reline)	1m 28s
vterm-yamatanooroti 3.3	32s
rake test 3.3	1m 22s
vterm-yamatanooroti head (latest reline)	38s
rake test head (latest reline)	1m 54s
vterm-yamatanooroti head	36s
rake test head	1m 51s
rake test truffleruby-head (latest reline)	2m 39s
rake test truffleruby-head	2m 44s
	36m 32s

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