Fix Infinity/NaN parsing to allow full set of values from VCF specification

[dtzeng]

What changes are proposed in this pull request?

Issue raised here: https://github.com/projectglow/glow/issues/517 In short, the VCF allows infinity/nan that follow this regex ^[-+]?(INF|INFINITY|NAN)$ case insensitively

The code that parses the INFO and genotype columns do not allow the full range of valid values.

How is this patch tested?

• [x] Unit tests
• [ ] Integration tests
• [x] Manual tests

Verified that unit tests failed before applying changes. And unit tests passed after applying my changes.

[williambrandler]

@henrydavidge could you take a look at this please?

[dtzeng]

What's the process to get this merged?

[williambrandler]

looks like the relevant tests passed, I don't see why this cannot be merged in

[williambrandler]

thanks @dtzeng for your contribution