Improve test logic

Retest the failed part of the test and call it recursively.
Remove the number of batches that are automatically divided when testing parameters.

v2rayN/ServiceLib/Resx/ResUI.Designer.cs

@@ -2094,6 +2094,15 @@ namespace ServiceLib.Resx {
             }
         }
         
+        /// <summary>
+        ///   查找类似 Starting retesting failed parts, {0} remaining. Press ESC to terminate... 的本地化字符串。
+        /// </summary>
+        public static string SpeedtestingTestFailedPart {
+            get {
+                return ResourceManager.GetString("SpeedtestingTestFailedPart", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   查找类似 Waiting for testing (press ESC to terminate)... 的本地化字符串。
         /// </summary>