BHV-10256: optimize event bubbling using cached bubble target

BHV-10256: optimize event bubbling using cached bubble target

This is a same PR with https://github.com/enyojs/enyo/pull/719 which is merged 2.4.0 but isn't merged 2.5.0

Enyo-DCO-1.1-Signed-off-by: Sungbae Cho sb.cho@lge.com