Add more SKIP_XXX in ClassReader
Following flags are useful to quickly scan a class. * SKIP_FIELDS_AND_METHODS Skips all fields and methods when we only get the class information (such as annotations, super class, interfaces, ...) * SKIP_CODE_INST It is NOT same with SKIP_CODE. SKIP_CODE will skip the code and code attributes. But if we want to get the attributes of code (such as LocalVariableTable for parameter name), we have to parse all code instructions. I think we can only skip to code instructions parsing and go to code attributes.