Remove from the Mnemonic enum: LDARB_X/LDARH_X/STLRB_X/STLRH_X (no
distinct byte/half acquire-release 'X' encoding exists -- LDARB/LDARH/
STLRB/STLRH already cover them), and the 12 redundant SME names
SME_LD1{B,H,W,D,Q}_ZA / SME_ST1{...}_ZA / SME_MOVA_TO_Z / SME_MOVA_TO_ZA
(same instructions as the canonical *_TILE / MOVA_*_FROM_* forms).
The builder generator now emits delegating aliases for the redundant SME
names (inst_sme_ld1b_za :: inst_sme_ld1b_tile, ...), so the convenient
names keep working and resolve to the canonical, decode-unambiguous
encodings. With XAR_Z landed, the arm64 Mnemonic enum is now 100%
covered: every entry has an encode form. 461 tests green.
fe7b81d64f