Re-apply "elf: Properly compute offsets of note descriptor and next note"

Re-apply "elf: Properly compute offsets of note descriptor and next note"

CORE PT_NOTE segments may have p_align values of 0 or 1.  gABI specifies
that PT_NOTE alignment should be aligned to 4 bytes for 32-bit objects
and to 8 bytes for 64-bit objects.  If segment alignment is less than 4,
we use 4 byte alignment.