Babel preset for modern JS engines like V8

[tido64]

For React Native apps that use a modern JS engine (such as V8), we can drop a number of Babel plugins from the Metro preset and reduce the amount of polyfills needed to lower to ES5.

• Do we create an entirely new preset?
  • Compatibility table: https://kangax.github.io/compat-table/es6/
• Can we use @babel/preset-env?
• How do we upstream this?

[afoxman]

How do you "target" a particular VM? Do you have one bundle built for V8 and another downlevel bundle for all other engines? This will need runtime/hosting support and make distribution a bit more complex, as the host will now need to request an engine-specific bundle.