ofz#3826 Divide-by-zero

with fLeftStart == 1.0 (is allowed, see comment at mfCut) the whole
BezierSegment is needed and does not need to be cut at all so best would be to
add it to 'while' loop, after that the 'rest' will be added anyways so, add
'fLeftStart < 1.0' or 'fLeftStart != 1.0' (since limited to [0.0 .. 1.0]) to
the while in line 120 should do it

Change-Id: Ida87e06247d169482df26e665985753e634e149e
Reviewed-on: https://gerrit.libreoffice.org/43935Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

basegfx/source/polygon/b2dpolygoncutandtouch.cxx

@@ -117,7 +117,7 @@ namespace basegfx
                             double fLeftStart(0.0);
 
                             // now add all points targeted to be at this index
-                            while(nNewInd < nTempPointCount && rTempPoints[nNewInd].getIndex() == a)
+                            while (nNewInd < nTempPointCount && rTempPoints[nNewInd].getIndex() == a && fLeftStart < 1.0)
                             {
                                 const temporaryPoint& rTempPoint = rTempPoints[nNewInd++];