fix(runtime-core): fix resolving assets from mixins and extends

fix #1963

packages/runtime-core/__tests__/helpers/resolveAssets.spec.ts

@@ -151,4 +151,62 @@ describe('resolveAssets', () => {
       expect(serializeInner(root)).toBe('<div>hello</div>')
     })
   })
+
+  test('resolving from mixins & extends', () => {
+    const FooBar = () => null
+    const BarBaz = { mounted: () => null }
+
+    let component1: Component | string
+    let component2: Component | string
+    let component3: Component | string
+    let component4: Component | string
+    let directive1: Directive
+    let directive2: Directive
+    let directive3: Directive
+    let directive4: Directive
+
+    const Base = {
+      components: {
+        FooBar: FooBar
+      }
+    }
+    const Mixin = {
+      directives: {
+        BarBaz: BarBaz
+      }
+    }
+
+    const Root = {
+      extends: Base,
+      mixins: [Mixin],
+      setup() {
+        return () => {
+          component1 = resolveComponent('FooBar')!
+          directive1 = resolveDirective('BarBaz')!
+          // camelize
+          component2 = resolveComponent('Foo-bar')!
+          directive2 = resolveDirective('Bar-baz')!
+          // capitalize
+          component3 = resolveComponent('fooBar')!
+          directive3 = resolveDirective('barBaz')!
+          // camelize and capitalize
+          component4 = resolveComponent('foo-bar')!
+          directive4 = resolveDirective('bar-baz')!
+        }
+      }
+    }
+
+    const app = createApp(Root)
+    const root = nodeOps.createElement('div')
+    app.mount(root)
+    expect(component1!).toBe(FooBar)
+    expect(component2!).toBe(FooBar)
+    expect(component3!).toBe(FooBar)
+    expect(component4!).toBe(FooBar)
+
+    expect(directive1!).toBe(BarBaz)
+    expect(directive2!).toBe(BarBaz)
+    expect(directive3!).toBe(BarBaz)
+    expect(directive4!).toBe(BarBaz)
+  })
 })