fix(v-on): refactor DOM event options modifer handling

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.

packages/runtime-core/src/component.ts

@@ -246,6 +246,8 @@ export interface ComponentInternalInstance {
   slots: InternalSlots
   refs: Data
   emit: EmitFn
+  // used for keeping track of .once event handlers on components
+  emitted: Record<string, boolean> | null
 
   /**
    * setup related
@@ -396,7 +398,8 @@ export function createComponentInstance(
     rtg: null,
     rtc: null,
     ec: null,
-    emit: null as any // to be set immediately
+    emit: null as any, // to be set immediately
+    emitted: null
   }
   if (__DEV__) {
     instance.ctx = createRenderContext(instance)