fix(rollup_bundle): add resolve({..., browser:true})

[IgorMinar]

This is useful for bundling zone.js and other npm packages that contains
the browser field in the package.json

[gregmagolan]

Just a note that the browser field will take precedence over module which may be undesirable in some cases since browser code will not be ES6 typically. https://github.com/rollup/rollup-plugin-node-resolve/blob/master/src/index.js#L140

Maybe this should option should be turned on with an attribute?

Also, this will hopefully land soon as well which will support es2015 needed to bundle rxjs: rollup/rollup-plugin-node-resolve#182 which means we could expose a mainFields attribute in rollup_bundle as well.

[alexeagle]

This PR ought to include a test of some kind. Also, could you explain why this change? (is there some accompanying change in Angular? what's wrong with how we load zone.js now?)

Per @gregmagolan comment, how can we even know what is the right set of attributes here? Users need browser field to resolve if and only if one of their packages uses it, but otherwise it's undesirable?

[filipesilva]

rollup/rollup-plugin-node-resolve#182 is now merged into Rollup.

[alexeagle]

Not planning to add features to old rollup-bundle rule, will be deleted by 1.0