More robust tests across all OS options, using xvfb #22

Job	Run time
Test on Java 8 on ubuntu-latest	32s
Test on Java 8 on macos-12	39s
Test on Java 8 on windows-latest	33s
Test on Java 11 on ubuntu-latest	27s
Test on Java 11 on macos-12	33s
Test on Java 11 on windows-latest	38s
Test on Java 11 on macos-latest	23s
Test on Java 16 on ubuntu-latest	28s
Test on Java 16 on macos-12	46s
Test on Java 16 on windows-latest	34s
Test on Java 17 on ubuntu-latest	22s
Test on Java 17 on macos-12	32s
Test on Java 17 on windows-latest	41s
Test on Java 17 on macos-latest	27s
Test on Java 19 on ubuntu-latest	22s
Test on Java 19 on macos-12	51s
Test on Java 19 on windows-latest	37s
Test on Java 19 on macos-latest	21s
Test on Java 21 on ubuntu-latest	23s
Test on Java 21 on macos-12	29s
Test on Java 21 on windows-latest	37s
Test on Java 21 on macos-latest	20s
	11m 35s

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