Create a new ExceptionTableEntry. Exception tables are of two kinds: either a normal one (with a Throwable as the
catch_type) or a finally clause (which has no catch_type). In the class file, the finally clause is represented
as catch_type == 0.
To create a finally clause with this method, pass in null for the catchType.
startPC - int
endPC - int
handlerPC - int
catchType - CPClass (if it's a normal catch) or null (if it's a finally clause).