Update to ELF Tool Chain r3223

Highlights (upstream revisions):

• Fix SHT_GROUP handling in elfcopy/strip (3206 3220 3221)
• Misc elfcopy / strip bug fixes (3215 3216 3217)
• Many C++ demangler improvements (3199 3200 3201 3202 3203 3204 3205 3208 3210 3211 3212)
• Improve GNU binutils compatibility in elfcopy / strip (3213 3214)
• Add -g option to readelf(1): dump contents of section groups (3219)
• Add EM_IAMCU 32-bit Intel MCU (3198)

Also add a compat #define for building with older FreeBSD ELF headers.
The GRP_COMDAT flag was added to elf_common.h in r283110, but it's not
available during the bootstrap build. It is also convenient to be able
to build on older hosts.

Thanks to antoine@ for tracking down issues through multiple exp-runs
and to kaiw@ for fixing.

PR: 198611 (exp-run), 200350
Sponsored by: The FreeBSD Foundation