kernel ELF: Reimplement Elf Branding, .note.ABI-tag

kernel ELF: Reimplement Elf Branding, .note.ABI-tag

Static executables built with the GNU gold linker are not recognized as
valid ELF binaries, although the same binaries built by ld linker did
work.

It was suspected that gold was keying off the .note.ABI-tag.  Primitive
support for this tag had been added years ago from NetBSD, and later
Corecode disabled it except for ELF program headers.

I removed all the .note.ABI-tag support that had been added after
DragonFly forked from FreeBSD and ported over FreeBSD's branding logic
and .note.ABI-tag support.  In particular, the branding logic a lot
cleaner now, and will easily support 32-bit binaries on x86_64 should
this feature arise in DragonFly in the future.

With these changes, gold can now build static executables that are
recognized and execute.  The Linuxolator had to be modified to work
with the new branding scheme as well (i386 only).