Remove incorrectly generated call to adaptivePredict

This particular call to adaptivePredict did not correctly match the decision number to the preceding setState() call. In addition, since this code is generated only for a positive closure, the only possible alternative is the one that enters the loop; error handling is deferred to the alternative(s) within the body of the closure.
adaptivePredict never returns -1; it could return ATN.INVALID_ALT_NUMBER
Merge pull request #532 from sharwell/codegen-fixes

Codegen fixes