Clip_Tests: Remove try/catch blocks

[ferdnyc]

UnitTest++ has its own exception handling (you can even CHECK_THROW() to test that a call throws an exception as expected), so the try/catch blocks in the Clip unit tests serve no purpose except to add unreachable code.

This PR replaces them with REQUIRE CHECK_EQUAL(true, success); checks on the result var from the previous call (the one that, when it was found false, the test used to throw()).

[ferdnyc]

I believe this should raise the internal coverage of our unit tests to 100%, meaning that every line of the test code (not the tested code) is reached during the test run. As it should be.

Now we just have to get the overall coverage up.

[codecov-io]

Codecov Report

Merging #468 into develop will increase coverage by 0.08%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop     #468      +/-   ##
===========================================
+ Coverage    48.04%   48.12%   +0.08%     
===========================================
  Files          128      128              
  Lines         9941     9934       -7     
===========================================
+ Hits          4776     4781       +5     
+ Misses        5165     5153      -12     

Impacted Files	Coverage Δ
tests/Clip_Tests.cpp	100.00% <100.00%> (+10.43%)	⬆️

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[ferdnyc]

Merging, as the change has the intended effect.