fix(remove): remove only body on ArrowFunctionExpression

[layershifter]

Applied change

This PR allow to remove only body of ArrowFunctionExpression, this means that egg will remain a valid function and can be callable.

fixture

import a from 'assert';

export const egg = () => a.ok();

current

import a from 'assert';

export const egg;

expected

import a from 'assert';

export const egg = () => {};