* i386.h: Remove NoModrm flag from all insns: it's never checked.
Add IsString flag to string instructions.
(IS_STRING): Don't define.
(LOCK_PREFIX_OPCODE, CS_PREFIX_OPCODE, DS_PREFIX_OPCODE): Define.
(ES_PREFIX_OPCODE, FS_PREFIX_OPCODE, GS_PREFIX_OPCODE): Define.
(SS_PREFIX_OPCODE): Define.