test: make nonce-srv-v2 / noncev2 the default (#8689)

This is now deployed in prod.

Author: jsha

test/config/wfe2.json

@@ -66,7 +66,7 @@
 					"domain": "service.consul"
 				}
 			],
-			"srvResolver": "nonce-srv",
+			"srvResolver": "nonce-srv-v2",
 			"timeout": "15s",
 			"noWaitForReady": true,
 			"hostOverride": "nonce.boulder"