Enable createEventHandle API for wWW test builds (facebook#19262)

Author: Brian Vaughn

packages/shared/forks/ReactFeatureFlags.testing.www.js

@@ -27,7 +27,7 @@ export const enableSchedulerDebugging = false;
 export const enableDeprecatedFlareAPI = true;
 export const enableFundamentalAPI = false;
 export const enableScopeAPI = true;
-export const enableCreateEventHandleAPI = false;
+export const enableCreateEventHandleAPI = true;
 export const warnAboutUnmockedScheduler = true;
 export const enableSuspenseCallback = true;
 export const warnAboutDefaultPropsOnFunctionComponents = false;