FWIW : after upgrading to 10.6.rc1 and running ptestong, I get the same permanent failures previously reported :
sage -t --long --warn-long 30.0 --random-seed=178148706330350151238968036871383560721 src/sage/libs/gap/element.pyx # Killed due to segmentation fault sage -t --long --warn-long 30.0 --random-seed=178148706330350151238968036871383560721 src/sage/coding/linear_code.py # 4 doctests failed sage -t --long --warn-long 30.0 --random-seed=178148706330350151238968036871383560721 src/sage/rings/real_mpfr.pyx # 1 doctest failed