Alternative fix for 'encompassing hole' tree support issue

[ThomasRahm]

Description

This pull request does 3 things:

1. It reverts [CURA-12153] Fix 'encompassing hole' issue (tree support). #2145 and adds an alternative solution for what it intended.
   I think explicitly excluding holes with branches inside them from being removed is better than re-adding the branches later.
   My opinion about the fix in [CURA-12153] Fix 'encompassing hole' issue (tree support). #2145:
   In the best case if the branches are added back, there is no difference between the hole being removed or not. Worst case something breaks:
   If I understood the change there correctly it adds all branches in a hole aka negative-holes in a positive-hole, as a positive-hole, which later is then reversed and added back to the support area as a negative-hole. This should mean that if support density is larger than 0 this fix will cause confused people wondering why suddenly the area around the branches is filled with support infill, but the branch itself is not:

This is what it looks with this pull request:

(Why the branch paths are different between these two screenshots is an investigation for another day)

2. It correctly adds the change from Fix Tree-support lines overlapping with the model #2088
   How the other solution, where I tried to solve it without an offset found its way back I do not understand. As seen by the example file given in the pull request [CURA-12153] Fix 'encompassing hole' issue (tree support). #2145 it sadly does not work and can cause inconsistent hole removal.

3. While debugging I noticed that this function takes longer than I would have expected. I found a small change that drastically increases the performance in this test-case. While it is not related to the things above, I don't see any reason to not include it.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• File from [CURA-12153] Fix 'encompassing hole' issue (tree support). #2145 its changes back-ported to a 5.8 branch, as I currently have issues compiling 5.9.

Checklist:

• My code follows the style guidelines of this project as described in UltiMaker Meta
• I have read the Contribution guide
• I have commented my code, particularly in hard-to-understand areas
• I have uploaded any files required to test this change

[ThomasRahm]

The diff reads a bit confusing. It does not handle me adding an if and converting the if after it to an else if particularly well, so here a visual aid:

If the diff confuses me (who has written the code) for like 5 to 10 minutes, anyone reviewing it could also be confused by it.

[rburema]

Thanks! The screenshots of the diff where helpful, it made it clear how small this fix is :-)