Circumvent more Green Hills compiler warnings

[chiphogg]

For get_value_result(), we split the implementation between two new
types: one for "trying to put a non-integer in an integral type", and
one for "everything else". We still assign the result to a constexpr
variable to force it to be evaluated at compile time.

For the other two, we use ternary operators to bring things into a
single line of code, splitting out into separate functions when that
makes sense.

Follow-on to #467.

[Copilot]

Pull Request Overview

This PR modifies compiler-specific code to circumvent Green Hills compiler warnings by restructuring control flow to use single expressions rather than multi-statement blocks. The changes focus on making functions technically "one-liners" to satisfy the compiler's requirements.

• Refactored get_value_result() into separate template structs for different cases
• Converted conditional logic to ternary operators in categorize_mag_label()
• Extracted helper function double_first_until_second() in ValueOfMaxFloatNotExceedingMaxInt

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
au/magnitude.hh	Splits get_value_result() into template specializations and converts categorize_mag_label() to nested ternary operators
au/overflow_boundary.hh	Converts if-else logic to ternary operator and extracts loop into separate helper function

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