Fix SingleConnectionPoolTest.should_throttle_requests()

Adjusts max in-flight requests based on number of connections to shards.
With the config that sets 1 connection per host but with 2 shards on that host,
there will be 2 connections. This results in twice as many in-flight requests.

Author: Bouncheck

driver-core/src/test/java/com/datastax/driver/core/SingleConnectionPoolTest.java

@@ -30,11 +30,12 @@ public class SingleConnectionPoolTest extends CCMTestsSupport {
   @Test(groups = "short")
   public void should_throttle_requests() {
     // Throttle to a very low value. Even a single thread can generate a higher throughput.
-    final int maxRequests = 10;
+    final int maxRequestsPerConnection = 10;
     cluster()
         .getConfiguration()
         .getPoolingOptions()
-        .setMaxRequestsPerConnection(HostDistance.LOCAL, maxRequests);
+        .setMaxRequestsPerConnection(HostDistance.LOCAL, maxRequestsPerConnection);
+    final int maxRequests = 10 * TestUtils.numberOfLocalCoreConnectionsSharded(cluster());
 
     // Track in flight requests in a dedicated thread every second
     final AtomicBoolean excessInflightQueriesSpotted = new AtomicBoolean(false);