Mutect2 germline resource can have split multiallelic format

[davidbenjamin]

See this forum issue: https://gatk.broadinstitute.org/hc/en-us/community/posts/25681424869787-Mutect2-Filtering-Discrepancy-with-Different-Versions-of-gnomAD-Germline-Data

[gatk-bot]

Github actions tests reported job failures from actions build 9107468050
Failures in the following jobs:

Test Type	JDK	Job ID	Logs
unit	17.0.6+10	9107468050.12	logs
unit	17.0.6+10	9107468050.1	logs
variantcalling	17.0.6+10	9107468050.2	logs

[gatk-bot]

Github actions tests reported job failures from actions build 9113421624
Failures in the following jobs:

Test Type	JDK	Job ID	Logs
unit	17.0.6+10	9113421624.12	logs
unit	17.0.6+10	9113421624.1	logs

[davidbenjamin]

@jamesemery Not DRAGEN!

[jamesemery]

One test case request that I don't think was covered by the tests you added but otherwise this looks good.