Implement a conversion from ValueDef into ProgramPoint.
Implement a conversion from ValueDef into ProgramPoint.

A ValueDef is really no more than a program point plus an
argument/result number.

sunfishcode/cretonne,sunfishcode/cretonne,stoklund/cretonne,stoklund/cretonne,sunfishcode/cretonne,stoklund/cretonne