perf(runtime-core): use feature flag for call to resolveMergedOptions (vuejs#12163)

Reduce bundle size when using `__VUE_OPTIONS_API__: false`

Author: skirtles-code

packages/runtime-core/src/component.ts

@@ -1008,7 +1008,7 @@ export function finishComponentSetup(
           instance.vnode.props &&
           instance.vnode.props['inline-template']) ||
         Component.template ||
-        resolveMergedOptions(instance).template
+        (__FEATURE_OPTIONS_API__ && resolveMergedOptions(instance).template)
       if (template) {
         if (__DEV__) {
           startMeasure(instance, `compile`)