Assemblyman William Boyland Jr. was convicted of extortion and soliciting bribes by a federal jury Thursday and immediately tossed in jail. The corrupt Brooklyn Democrat closed his eyes and held his head with both hands as the jury foreman pronounced him guilty of all 21 counts in the indictment. Assistant U.S. Attorney Robert Capers then told the judge that Boyland, 43, broke the law even while on trial. FBI agents surveilled him driving in Brooklyn and Manhattan recently despite the suspensions of his license, registration and auto insurance. …