swap test order for segment override applicability

it is almost always the case that self.prefixes.segment == Segment::DS,
meaning testing for it first avoids checking
`self.operands[op].is_memory()` later. this overall avoids a few
instructions in the typical path, rather than checking `is_memory()`
first (which would always be true in the places this function is called
from)

0 files changed, 0 insertions, 0 deletions