MIDEAST STOCKS-Banks boost Saudi for eighth straight day

* Saudi bond issue eases investor jitters * Banks continue to lead market higher, NCB leaps * Petrochemicals underperform market after oil pulls back * Qatar's GISS, Qatari Investors Group plunge * Dubai's GFH and Arabtec surge, others barely move By Andrew Torchia DUBAI, Oct 30 (Reuters) - Strong banking shares boosted Saudi Arabia's stock market for an eighth straight day on Sunday but the rest of the region was sluggish in response to soft oil prices and global bourses, while Qatari equities