Bring in some performance improvements from genomicsdb

[nalinigans]

No description provided.

[nalinigans]

@gokalpcelik can you check if the improvements in branch [genomicsdb_perf](https://github.com/broadinstitute/gatk/tree/genomicsdb_perf) help with #8989?

[lbergelson]

@nalinigans Thank you!

[nalinigans]

@gokalpcelik, any updates on whether you could test the performance improvements? If yes, I can make a maven product release of GenomicsDB. Thanks.

[gokalpcelik]

@nalinigans Indeed yes. I was able to confirm that memory usage is much better now although not at 4.1 levels but still it does not die on OOM. Fidelity is also OK in my testing so if the team says OK and you are OK we can give it a go.

[gokalpcelik]

@nalinigans
I remember that you said it is slower now compared to older implementation. My findings are also similar. It is slower (about 1.1~1.3 times) compared to 4.1 and 4.2 and beyond. Did you have a chance to add additional tweaks that you mentioned?
No, I have not a chance for additional tweaks yet. But, will keep it in mind to check this soon.

[nalinigans]

@gokalpcelik @lbergelson, I have changed the snapshot release used for testing to the released genomicsdb 1.5.5 jar. Please feel free to review and pull in this PR. Thanks.