Remove the IFI tests

[SamuelTrahanNOAA]

Description

Due to security and intellectual property restrictions, the in-flight icing library (libIFI) tests are only run on Acorn. The library is expected to never be run in the inline post. Continuing to test it that way only adds unnecessary work. (This was decided at an August 27, 2024 meeting between libIFI stakeholders about libIFI testing.)

Solution

Remove the tests.

Alternatives

Keep testing a feature that won't be used.