fix the gqr panic on 7, operand accessors, clean up a bunch of tests,
ppc64le helper for InstDecoder, get derives in better shape, some more
docs, fix confusion about when lk/aa bits are set for branches, make
`BI` consistently a `CrBit`.
very stale test expectations
display is "less" gross now
get more isa rejection for yet-unsupported arches more in place
mtsrd operand order, dcbi/dcbt/dcbz