Various cleanups in pkey tests #1303

Job	Run time
openssl-1.0.2u	51s
openssl-1.1.0l	59s
openssl-1.1.1w	1m 2s
openssl-3.0.15	1m 4s
openssl-3.1.7	1m 3s
openssl-3.2.3	1m 1s
openssl-3.3.2	1m 4s
openssl-3.4.0	57s
openssl-master	3m 50s
libressl-3.1.5	57s
libressl-3.2.7	58s
libressl-3.3.6	1m 1s
libressl-3.4.3	1m 7s
libressl-3.5.3	59s
libressl-3.6.3	59s
libressl-3.7.3	54s
libressl-3.8.4	1m 3s
libressl-3.9.2	57s
libressl-4.0.0	1m 2s
openssl-3.0.15 with fips provider	57s
openssl-3.1.7 with fips provider	50s
openssl-3.2.3 with fips provider	55s
openssl-3.3.2 with fips provider	50s
openssl-3.4.0 with fips provider	48s
openssl-master with fips provider	3m 40s
openssl-3.4.0 without legacy provider	1m 4s
ruby-versions / Generate Ruby versions	1s
ubuntu-22.04 2.7	59s
ubuntu-22.04 3.0	56s
ubuntu-22.04 3.1	1m 0s
ubuntu-22.04 3.2	59s
ubuntu-22.04 3.3	57s
ubuntu-22.04 3.4	59s
ubuntu-22.04 head	59s
ubuntu-22.04 truffleruby	1m 40s
ubuntu-22.04 truffleruby-head	1m 47s
ubuntu-20.04 2.7	59s
ubuntu-20.04 3.0	55s
ubuntu-20.04 3.1	56s
ubuntu-20.04 3.2	57s
ubuntu-20.04 3.3	54s
ubuntu-20.04 3.4	55s
ubuntu-20.04 head	55s
ubuntu-20.04 truffleruby	1m 35s
ubuntu-20.04 truffleruby-head	1m 49s
macos-latest 2.7	51s
macos-latest 3.0	42s
macos-latest 3.1	47s
macos-latest 3.2	39s
macos-latest 3.3	44s
macos-latest 3.4	39s
macos-latest head	40s
macos-latest truffleruby	1m 9s
macos-latest truffleruby-head	1m 28s
windows-latest 2.7	5m 1s
windows-latest 3.0	4m 27s
windows-latest 3.1	4m 32s
windows-latest 3.2	4m 31s
windows-latest 3.3	6m 10s
windows-latest 3.4	6m 39s
windows-latest head	5m 9s
windows-latest ucrt	4m 9s
windows-latest mswin	3m 2s
	1h 42m 23s

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