fix(config): restore maxFastForwardNum to correct default value

Author: jwrct

framework/src/main/java/org/tron/core/config/args/Args.java

@@ -129,7 +129,7 @@ public static void clearParam() {
     PARAMETER.activeNodes = new ArrayList<>();
     PARAMETER.passiveNodes = new ArrayList<>();
     PARAMETER.fastForwardNodes = new ArrayList<>();
-    PARAMETER.maxFastForwardNum = 3;
+    PARAMETER.maxFastForwardNum = 4;
     PARAMETER.nodeChannelReadTimeout = 0;
     PARAMETER.maxConnections = 30;
     PARAMETER.minConnections = 8;