Fix test_pkey_dsa.rb in FIPS. #980

Job	Run time
openssl-1.0.2u	2m 32s
openssl-1.1.0l	1m 33s
openssl-1.1.1w	1m 48s
openssl-3.0.13	3m 0s
openssl-3.1.5	2m 54s
openssl-3.2.1	3m 19s
libressl-3.1.5	2m 3s
libressl-3.2.7	2m 12s
libressl-3.3.6	2m 15s
libressl-3.4.3	2m 19s
libressl-3.5.3	2m 14s
libressl-3.6.3	2m 15s
libressl-3.7.3	2m 15s
libressl-3.8.2	2m 11s
openssl-3.0.13 fips	2m 43s
openssl-3.1.5 fips	2m 57s
openssl-3.2.1 fips	3m 16s
openssl-head	3m 23s
openssl-head fips	3m 16s
openssl-head no-legacy	3m 23s
ruby-versions / Generate Ruby versions	2s
ubuntu-22.04 2.7	57s
ubuntu-22.04 3.0	50s
ubuntu-22.04 3.1	59s
ubuntu-22.04 3.2	58s
ubuntu-22.04 3.3	54s
ubuntu-22.04 head	55s
ubuntu-22.04 truffleruby	1m 27s
ubuntu-22.04 truffleruby-head	1m 30s
ubuntu-20.04 2.7	53s
ubuntu-20.04 3.0	53s
ubuntu-20.04 3.1	54s
ubuntu-20.04 3.2	51s
ubuntu-20.04 3.3	51s
ubuntu-20.04 head	51s
ubuntu-20.04 truffleruby-head	1m 29s
macos-latest 2.7	1m 17s
macos-latest 3.0	54s
macos-latest 3.1	1m 9s
macos-latest 3.2	58s
macos-latest 3.3	1m 48s
macos-latest head	58s
macos-latest truffleruby-head	1m 31s
windows-latest 2.7	5m 0s
windows-latest 3.0	4m 25s
windows-latest 3.1	4m 40s
windows-latest 3.2	4m 23s
windows-latest 3.3	5m 8s
windows-latest ucrt	3m 26s
windows-latest mswin	3m 12s
	1h 45m 51s

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