Inconsistency between `findAllAxialMeshPoints()` and `getAxialMesh()`

[albeanth]

core.findAllAxialMeshPoints() includes 0.0 in its return. https://github.com/terrapower/armi/blob/1990fcd5c77d11797f41d29212b3d17a82ad1ed4/armi/reactor/reactors.py#L1810-L1813

assembly.getAxialMesh() does not https://github.com/terrapower/armi/blob/1990fcd5c77d11797f41d29212b3d17a82ad1ed4/armi/reactor/assemblies.py#L372-L375

This can be confusing in some instances and is an opportunity to improve consistency amongst related methods. An example -- https://github.com/terrapower/armi/blob/1990fcd5c77d11797f41d29212b3d17a82ad1ed4/armi/reactor/converters/geometryConverters.py#L1097-L1104

A fix could be as simple as initializing meshVals with 0.0. One would just need to resolve dependencies on assembly.getAxialMesh https://github.com/terrapower/armi/blob/1990fcd5c77d11797f41d29212b3d17a82ad1ed4/armi/reactor/assemblies.py#L395-L414

[onufer]

setBlockMesh also doesn't expect 0.0. Consistency is important, and @ntouran and others agree we should be 0.0 inclusive to be explicit. Also, bottom is not always guaranteed to be 0.0 (could be negative for some systems)

[albeanth]

A note to my future self of an instance where there is 0.0 inconsistency.

https://github.com/terrapower/armi/blob/20ca6877c2e2221bc3e3521cf9e827cf2d4a4376/armi/reactor/reactors.py#L1692-L1696

[john-science]

@albeanth This ticket didn't get on my radar two years ago.

1. We should talk about it.
2. Should we mark this ticket as "bug"?

[albeanth]

@john-science sure, let's chat.

I don't think it's a bug but rather a questionable implementation/design choice that could be improved.