movslq instruction fails roundtrip tests

[pnwamk]

E.g., adding the test ("movslq 0x601018,%rax", ["movslq 0x601018,%rax"]) to the twoOperandOpcodes block of round trip tests causes a failure:

      movslq 0x601018,%rax:                     FAIL
        tests/Roundtrip.hs:297:
        Assembled bytes
        
        [II {iiLockPrefix = NoLockPrefix, iiAddrSize = Size64, iiOp = "movsxd", iiArgs = [(QWordReg rax,OpType ModRM_reg QSize),(Mem32 (Addr_64 ds Nothing Nothing (Disp32 0x601018)),OpType ModRM_rm DSize)], iiPrefixes = Prefixes {_prLockPrefix = NoLockPrefix, _prSP = SegmentPrefix {unwrapSegmentPrefix = 0}, _prREX = 0b01001000, _prVEX = Nothing, _prASO = False, _prOSO = False}, iiRequiredPrefix = Nothing, iiOpcode = [99], iiRequiredMod = Nothing, iiRequiredReg = Nothing, iiRequiredRM = Nothing}]
        Length: 7 (0x7) bytes
        0000:   48 63 05 18  10 60 00                                Hc...`.
        
        expected: "Hc\EOT%\CAN\DLE`\NUL"
         but got: "Hc\ENQ\CAN\DLE`\NUL"

[pnwamk]

Minor update: just chatted with @travitch and we're waiting on #17 for this PR