Tests

ci: also test against jdk 21 (#158) #364

Job	Run time
test-ubuntu-graalvm-native	1m 41s
test-ubuntu-temurin@8	59s
test-ubuntu-graalvm-community-native	1m 12s
test-windows-temurin@8	1m 7s
test-macOS-graalvm-native	1m 38s
test-ubuntu-temurin@11	36s
test-macOS-graalvm-community-native	1m 39s
test-macOS-temurin@11	1m 15s
test-windows-graalvm-native	2m 40s
test-windows-graalvm-community-native	2m 14s
test-windows-temurin@11	1m 13s
test-ubuntu-temurin@17	59s
test-macOS-temurin@17	1m 3s
test-windows-temurin@17	1m 22s
test-ubuntu-temurin@21	36s
test-macOS-temurin@21	1m 15s
test-windows-temurin@21	1m 11s
	22m 40s

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