ref(ember): Silence deprecation warnings in beta (#3346)

* ref(ember): Silence deprecation warnings in beta

We can deal with deprecations once they hit mainline, this should hopefully silence deprecations in the scenarios so we can see failures more easily and not spit out too many logs

Author: k-fish

packages/ember/tests/dummy/app/initializers/deprecation.js

@@ -0,0 +1,13 @@
+import { registerDeprecationHandler } from '@ember/debug';
+
+export function initialize() {
+  registerDeprecationHandler((message, options, next) => {
+    if (options && options.until && options.until !== '3.0.0') {
+      return;
+    } else {
+      next(message, options);
+    }
+  });
+}
+
+export default { initialize };