Fix history-saving feature #2184

Job	Run time
ruby-versions / Generate Ruby versions	2s
vterm-yamatanooroti 2.7 (latest reline)	1m 7s
vterm-yamatanooroti 2.7	1m 11s
vterm-yamatanooroti 3.0 (latest reline)	46s
vterm-yamatanooroti 3.0	33s
vterm-yamatanooroti 3.1 (latest reline)	39s
vterm-yamatanooroti 3.1	41s
vterm-yamatanooroti 3.2 (latest reline)	34s
vterm-yamatanooroti 3.2	36s
vterm-yamatanooroti head (latest reline)	40s
vterm-yamatanooroti head	35s
rake test 2.7 (latest reline)	43s
rake test 2.7	45s
rake test 3.0 (latest reline)	27s
rake test 3.0	26s
rake test 3.1 (latest reline)	40s
rake test 3.1	28s
rake test 3.2 (latest reline)	35s
rake test 3.2	26s
rake test head (latest reline)	30s
rake test head	29s
rake test truffleruby-head (latest reline)	5m 49s
rake test truffleruby-head	6m 49s
	25m 31s

Provide feedback