Fix node make extension for building chrome

Fixes #3127.

The problem was that `node make extension` build for both Firefox and Chrome. Both of these build steps require calling `target.bundle()`. However, it is only called once since `make.js` optimizes to run each build target once. However, since we want to bundle differently between Firefox and Chrome (and other targets), the fix is to pass a parameter to `target.bundle()` so that it is executed each time it is called.