Wrong distance computation has been corrected.
Some test-cases have been corrected according to their new behavior. Namely, built (by approximation algorithm) curve(s) has changed its geometrical position.
1. tests/blend/simple/X4
It is not a regression because the result is not correct on both MASTER and FIX (see explanation in the issue #26740). This problem is expected to be solved after porting Fillet-algorithm to new Boolean operation. Old Boolean operations do not cover Edge-Edge tangent-zone by vertex.
2. tests/bugs/modalg_6/bug27341_318
"checknbshapes" has been deleted in order to avoid non-stable behavior (see issue #29360) of this test case. New result is OK on both Linux and Windows platform.