Having ItnNeither WaynIrwin Shaw: Acceptable Losses;nArbor House; New York.nby Allen BrodskynIrwin Shaw has caught himselfnin a bind. He wants his novels tonhave mass appeal, so he adornsnhis characters and plots withnadolescent fantasies. Mild-mannerednmen are incredibly attractivento beautiful women andnhave aflfairs with one .glamorousnbeauty after another. Shaw'snheroes . . .