libdw, readelf: Make sure there is enough data to read full aranges header.

libdw, readelf: Make sure there is enough data to read full aranges header.

dwarf_getaranges didn't check if there was enough data left to read both
the address and segment size. readelf didn't check there was enough data
left to read the segment size.

https://sourceware.org/bugzilla/show_bug.cgi?id=23541

Signed-off-by: Mark Wielaard <mark@klomp.org>