Revert "elf: Properly compute offsets of note descriptor and next note"

Revert "elf: Properly compute offsets of note descriptor and next note"

This reverts commit 650444eb540f9fd85e821567a3f943b4bc41b8be.

With this patch, running the GDB test case gdb.base/auxv.exp is stuck in
an infinite loop, consuming memory to the point that it renders the
machine unusable. I am reverting it so we can take our time to
investigate while not killing all the developers' machines.