Fix IsKernelFunction

[markuspf]

Previously this returned False for certain functions installed as kernel functions, and then crashed.

[codecov-io]

Current coverage is 48.97% (diff: 100%)

Merging #876 into master will increase coverage by <.01%

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[ChrisJefferson]

This is the correct fix for this problem.

Going to be picky, and ask for a couple more tests (mainly, a couple of non-functions, an int and a record perhaps? as those are the things that were causing crashes?)

[markuspf]

Actually what was causing the segfault was METHODS_OPERATION(\=,2)[34] in my GAP session (equality test for 32bit associative words).

What is slightly misleading is that

gap> IsKernelFunction(Size);
true

Sure, operations are callable, so I'd gather this constitutes IsFunction. Whether it constitutes IsKernelFunction is another question though...

[markuspf]

Oh, and I added tests for an integer and a record.