Hi, the gdb.pie/break.exp change would be worth checking more but this is based on the old PIE patch with various known problems and for RHEL-6 there will be a different/new PIE patch implementation.
Also the gdb.base/bigcore.exp and gdb.base/follow-child.exp changes would be worth checking if the change is stable across multiple runs of the specific testcase. You can also check gdb.log differences, sometimes it is apparent the change is OK. Otherwise if the change is stable across multiple runs and it is not obvious to you why it did change as you already have the machine ready could you please provide the hostname/password/etc. there? Thanks, Jan