In an upcoming commit the history map will be changed so that it
contains explicit entries for instructions that clobber preceding debug
values, rather than Begin- End range pairs, so generalize the name to
Also, prefix the iterator variable names in buildLocationList() with
"E". In an upcoming commit the entry will have query functions such as
"isD(e)b(u)gValue", which could at a glance make one confuse it for
iterations over MachineInstrs, so make the iterator names a bit more
distinct to avoid that.