[lld] [ELF/AArch64] Add support to some GD/LE/IS TLS relocations
This patch adds some TLS relocations and relaxations for AArch64.
Some Global-Dynamic relocation are handled by optimizing them to
Local-Exec (Initial-Exec is not yet supported). They are:
Also some Init-Exec is optimized to Local-Exec if possible. They are:
Finally some Local-Exec relocation are handled in relocateOne:
This work is mainly for compiler bootstrap, where static binaries is
showing good progress (although shared object still lacking support
from both TLS aarch64 backend and some other issues).