Add support for IO#timeout. #940

Job	Run time
openssl-1.0.2u	2m 38s
openssl-1.1.0l	1m 32s
openssl-1.1.1w	1m 49s
ruby-versions / Generate Ruby versions	2s
openssl-3.0.12	2m 50s
openssl-3.1.4	2m 50s
openssl-3.2.0	3m 26s
libressl-3.1.5	2m 5s
libressl-3.2.7	2m 12s
libressl-3.3.6	2m 14s
libressl-3.4.3	2m 29s
libressl-3.5.3	2m 15s
libressl-3.6.3	2m 32s
libressl-3.7.3	2m 26s
libressl-3.8.1	2m 12s
openssl-3.0.12 fips	2m 39s
openssl-3.1.4 fips	2m 53s
openssl-3.2.0 fips	3m 22s
openssl-head	3m 25s
openssl-head fips	3m 14s
ubuntu-22.04 2.7	1m 2s
ubuntu-22.04 3.0	1m 0s
ubuntu-22.04 3.1	59s
ubuntu-22.04 3.2	56s
ubuntu-22.04 3.3	59s
ubuntu-22.04 head	53s
ubuntu-22.04 truffleruby	1m 29s
ubuntu-22.04 truffleruby-head	1m 31s
ubuntu-20.04 2.7	56s
ubuntu-20.04 3.0	51s
ubuntu-20.04 3.1	56s
ubuntu-20.04 3.2	59s
ubuntu-20.04 3.3	53s
ubuntu-20.04 head	47s
ubuntu-20.04 truffleruby-head	1m 22s
macos-latest 2.7	2m 0s
macos-latest 3.0	1m 24s
macos-latest 3.1	1m 21s
macos-latest 3.2	59s
macos-latest 3.3	1m 21s
macos-latest head	55s
macos-latest truffleruby-head	1m 54s
windows-latest 2.7	5m 3s
windows-latest 3.0	3m 49s
windows-latest 3.1	4m 4s
windows-latest 3.2	4m 3s
windows-latest 3.3	4m 24s
windows-latest ucrt	3m 49s
windows-latest mswin	3m 26s
	1h 43m 10s

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