revert change - dump arp and fdb for reconciliation

scripts/fast-reboot

@@ -41,6 +41,8 @@ EXIT_FILE_SYSTEM_FULL=3
 EXIT_NEXT_IMAGE_NOT_EXISTS=4
 EXIT_ORCHAGENT_SHUTDOWN=10
 EXIT_SYNCD_SHUTDOWN=11
+EXIT_FAST_REBOOT_DUMP_FAILURE=12
+EXIT_FILTER_FDB_ENTRIES_FAILURE=13
 EXIT_COUNTERPOLL_DELAY_FAILURE=14
 EXIT_DB_INTEGRITY_FAILURE=15
 EXIT_NO_CONTROL_PLANE_ASSISTANT=20
@@ -601,6 +603,28 @@ else
     load_kernel
 fi
 
+if [[ "$REBOOT_TYPE" = "fast-reboot" ]]; then
+    # Dump the ARP and FDB tables to files also as default routes for both IPv4 and IPv6
+    # into /host/fast-reboot
+    DUMP_DIR=/host/fast-reboot
+    mkdir -p $DUMP_DIR
+    FAST_REBOOT_DUMP_RC=0
+    /usr/local/bin/fast-reboot-dump.py -t $DUMP_DIR || FAST_REBOOT_DUMP_RC=$?
+    if [[ FAST_REBOOT_DUMP_RC -ne 0 ]]; then
+        error "Failed to run fast-reboot-dump.py. Exit code: $FAST_REBOOT_DUMP_RC"
+        unload_kernel
+        exit "${EXIT_FAST_REBOOT_DUMP_FAILURE}"
+    fi
+    FILTER_FDB_ENTRIES_RC=0
+    # Filter FDB entries using MAC addresses from ARP table
+    /usr/local/bin/filter_fdb_entries -f $DUMP_DIR/fdb.json -a $DUMP_DIR/arp.json -c $CONFIG_DB_FILE || FILTER_FDB_ENTRIES_RC=$?
+    if [[ FILTER_FDB_ENTRIES_RC -ne 0 ]]; then
+        error "Failed to filter FDb entries. Exit code: $FILTER_FDB_ENTRIES_RC"
+        unload_kernel
+        exit "${EXIT_FILTER_FDB_ENTRIES_FAILURE}"
+    fi
+fi
+
 init_warm_reboot_states
 
 setup_control_plane_assistant
@@ -631,15 +655,6 @@ if [[ "$REBOOT_TYPE" = "fast-reboot" ]]; then
         unload_kernel
         exit "${EXIT_COUNTERPOLL_DELAY_FAILURE}"
     fi
-
-    # Clear all routes except of default routes for faster reconciliation time.
-    sonic-db-cli APPL_DB eval "
-        for _, k in ipairs(redis.call('keys', '*')) do
-            if string.match(k, 'ROUTE_TABLE:') and not string.match(k, 'ROUTE_TABLE:0.0.0.0/0') and not string.match(k, 'ROUTE_TABLE:::/0') then \
-                redis.call('del', k)
-            end
-        end
-    " 0 > /dev/null
 fi
 
 # We are fully committed to reboot from this point on because critical