wasm-objdump should have a way to only show specific functions

[eholk]

I'm debugging a Wasm compile error in a specific function. It'd be nice to be able to limit the disassembly dump to only a specific function or functions. For example:

wasm-objdump -d out.wasm --functions=13,64

This would only show the disassembly for functions 13 and 64. For bonus points, it'd be nice to be able to specify their name if a names section is present.