Add LocalVariableTable for output to support debug

[warmthdawn]

As title， write local variable table to the compile output in order to support debug. (The debug is provided by a vscode plugin I'm developing) https://github.com/warmthdawn/zs-debug-adapter

[warmthdawn]

As for why I didn't write the final output in end(), first of all, there are some methods (such as lambda-generated temporary methods) that don't need these. Second, the generation needs to get something related to Environment, and it seems too much for MethodOutput.

this pr is intended to mc1.12, BTW, for zencode, since it wirtes the 'end' immediately next to start label, i wonder whether there are any problems.