fix#1567
Previously multiple `v-on` handlers with different event attach option
modifers (`.once`, `.capture` and `.passive`) are generated as an array
of objects in the form of `[{ handler, options }]` - however, this
makes it pretty complex for `runtime-dom` to properly handle all
possible value permutations, as each handler may need to be attached
with different options.
With this commit, they are now generated as event props with different
keys - e.g. `v-on:click.capture` is now generated as a prop named
`onClick.capture`. This allows them to be patched as separate props
which makes the runtime handling much simpler.
