Add corner mosaic tests to mpp suite

[vithikashah001]

Description
the code integrates existing corner mosaic tests into the mpp unit test suite

Fixes # (issue)

How Has This Been Tested?
with autotools on amd box

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• New check tests, if applicable, are included
• make distcheck passes

[J-Lentz]

Since the values below have been changed, this comment should either be updated or deleted.

[J-Lentz]

I think the best place for this figure would probably be in a description at the top of the file.

[J-Lentz]

Same comment as above regarding this figure.

[J-Lentz]

Thanks Vithika!

[rem1776]

Looks good!