test: fix race in redis-4 tests (open-telemetry#1863)

The beforeEach() hook was not awaited, so afterEach() could run before
it completed, resulting in a client.disconnect() that rejects, and a
mocha hook that calls done() twice.

Refs: open-telemetry#1860

Co-authored-by: Marc Pichler <marc.pichler@dynatrace.com>

plugins/node/opentelemetry-instrumentation-redis-4/test/redis.test.ts

@@ -71,7 +71,7 @@ describe('redis@^4.0.0', () => {
     client = createClient({
       url: redisTestUrl,
     });
-    context.with(suppressTracing(context.active()), async () => {
+    await context.with(suppressTracing(context.active()), async () => {
       await client.connect();
     });
   });