[gravel-gateway-compat] create new instance of gateway for test

Author: Geof Holbrook

test/pushgatewayTest.js

@@ -102,12 +102,16 @@ describe.each([
 					.post('/metrics', body)
 					.reply(200);
 
-				instance.requireJobName = false;
+				instance = new Pushgateway(
+					'http://192.168.99.100:9091',
+					{
+						timeout: 10,
+						requireJobName: false,
+					},
+					registry,
+				);
 
-				return instance.pushAdd().then(() => {
-					instance.requireJobName = true;
-					return expect(mockHttp.isDone());
-				});
+				return instance.pushAdd().then(() => expect(mockHttp.isDone()));
 			});
 		});