Fix x86-linux Dockerfile (#502) #1016

Job	Run time
Bundle install in Dockerfile	1m 11s
oxi-test (ruby=3.0, os=ubuntu-latest)	1m 10s
oxi-test (ruby=3.2, os=ubuntu-latest)	1m 8s
oxi-test (ruby=3.3, os=ubuntu-latest)	1m 21s
oxi-test (ruby=3.0, os=windows-latest)	4m 4s
oxi-test (ruby=3.2, os=windows-latest)	4m 8s
oxi-test (ruby=3.3, os=windows-latest)	4m 34s
oxi-test (ruby=3.0, os=macos-latest)	57s
oxi-test (ruby=3.2, os=macos-latest)	53s
oxi-test (ruby=3.3, os=macos-latest)	1m 14s
magnus-0.5 (ruby=3.0, os=ubuntu-latest)	1m 26s
magnus-0.5 (ruby=3.2, os=ubuntu-latest)	1m 18s
magnus-0.5 (ruby=3.3, os=ubuntu-latest)	1m 17s
magnus-0.5 (ruby=3.0, os=windows-latest)	4m 54s
magnus-0.5 (ruby=3.2, os=windows-latest)	4m 21s
magnus-0.5 (ruby=3.3, os=windows-latest)	5m 38s
magnus-0.5 (ruby=3.0, os=macos-latest)	1m 24s
magnus-0.5 (ruby=3.2, os=macos-latest)	1m 4s
magnus-0.5 (ruby=3.3, os=macos-latest)	1m 13s
magnus-head (ruby=3.0, os=ubuntu-latest)	2m 3s
magnus-head (ruby=3.2, os=ubuntu-latest)	2m 6s
magnus-head (ruby=3.3, os=ubuntu-latest)	2m 17s
magnus-head (ruby=3.0, os=windows-latest)	6m 8s
magnus-head (ruby=3.2, os=windows-latest)	5m 58s
magnus-head (ruby=3.3, os=windows-latest)	6m 47s
magnus-head (ruby=3.0, os=macos-latest)	2m 8s
magnus-head (ruby=3.2, os=macos-latest)	1m 38s
magnus-head (ruby=3.3, os=macos-latest)	1m 25s
	1h 13m 45s

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