AArch64 decoder doesn't set the raw bits

It looks like if we use decode_from_copy() to decode from address X as though it were at address Y (for purposes of PC-relative operands), something that is common for drmemtrace address trace post-processing and analysis, the AArch64 decoder sets the translation target (obtainable via instr_get_app_pc()) to Y as expected but does not set the raw bits and thus instr_get_raw_bits() returns NULL rather than X.