Increasing Code Coverage

[john-science]

What is the change?

I added code coverage to:

• CaseSuite.compare()
• Assembly.getBIndexFromZIndex()
• Assembly.getElevationBoundariesByBlockType()

An I removed two unused methods:

• Reactor.getAllNuclidesIn()
• armi.utils.plotting.plotTriangleFlux()

Why is the change being made?

I am just trying to increase our code coverage.

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Checklist

• This PR has only one purpose or idea.
• Tests have been added/updated to verify any new/changed code.

• The code style follows good practices.
• The commit message(s) follow good practices.

• The release notes have been updated if necessary.
• The documentation is still up-to-date in the doc folder.
• The dependencies are still up-to-date in pyproject.toml.

[john-science]

Geez. Moving the needle on our code coverage is hard these days. Here's the end result of this PR:

COVERAGE: 89.098% (+0.3%) FROM 88.827%

https://coveralls.io/builds/66071414

At least the code coverage is up over 89%.

[opotowsky]

This is just deleting unused code and adding a test outside a few non-requirements-associated docstring updated. Approve!