Changes
/* Z80: ED B9 cpd(r) / ED B1 cpi(r) */
Problem here : CPDR and CPIR has same implementation than ED A9 CPD and ED A1 CPI.
Solved by Sorgelig (does not run pass plustest.dsk testbench 5 in r005.8.16.2 but does pass it on Sorgelig MiSTer fork version)
In fact it is more difficult instruction that I was thinking, if you watch at it, it shall take only 4 NOPs maximum but in plustest.dsk it does take 6/4 NOPs. In fact C9 RET seem also used here, as sub instruction. Do remark that CPD and CPI does take 4 NOPs, so here CPDR/CPIR does not has same implementation than CPD/CPI.
