4.7.20.1: Loosen offset of annotated instanceof

Per http://mail.openjdk.java.net/pipermail/compiler-dev/2016-January/009921.html, the offset_target item of a target_info union should not commit to an instanceof expression being implemented with an instanceof bytecode:

"The value of the offset item specifies the code array offset of either the /*DELETE*/instanceof/*DELETE*/ bytecode instruction corresponding to the instanceof expression, the new bytecode instruction corresponding to the new expression, or the bytecode instruction corresponding to the method reference expression."