fix: should correctly resolve extends or mixins assets

[HcySunYang]

Fix: #1963

[yyx990803]

We have to avoid mutating the original options because it may be used by other components as base for extends or as a mixin.

This regression was introduced by a75b8a2 - I originally removed components and directives from component instance to reduce memory usage, but in this case we have to add them back. But we can create them only when the component actually has mixins or extends (see 0cb7f7f)