Modeling Algorithms - BOPAlgo_BuilderFace cannot build new faces correctly

The fix for the issue #0029421 creates three faces (as it is needed). However, the face f_3 is invalid in terms of BRepCheck.

I have attached it in the file Attachment 2 (BIN) (is opened by "binrestore" DRAW-command).

Please note, that visually this face seems to be OK. So, maybe here BRepCheck algorithm works wrongly. It should be analyzed.

Faulty status is returned by BRepCheck_Wire::Closed2d() method. It uses BRepTools_WireExplorer algorithm, which finds only one edge in the wire (in spite of wire's containing 4 edges).

binrestore Attachment 2 (BIN) ff
explode ff w
wexplo ff_1 ff
puts [llength [directory WEDGE_*]]
# 1 but must be 4

Please note, if we use BRepTools_WireExplorer only for 3D-space then it works correctly:

binrestore Attachment 2 (BIN) ff
explode ff w
wexplo ff_1
puts [llength [directory WEDGE_*]]
# 4 ==> OK

As result, the tests "bugs modalg_7 bug29807_b5a" and "bugs modalg_7 bug29807_b4a" changes self behavior. The number of entities has become as expected but

checkshape result 

finds faulty entities.

Please note that the degenerated edge is not trimmed by the intersection point with another edge. See Attachment 3 (PNG) attached picture, where p-curve of Attachment 2 (BIN) is shown.

I think, it is a problem of Boolean operation in "bugs modalg_7 bug29807_b5a" and "bugs modalg_7 bug29807_b4a" test cases.