feature: extend extra features to operate the radixtree. (api7#128)

* extend operation for the radixtree

* fix: update route in order while changing route's priority

* combine duplicate codes.

* added use case using Test:Nginx

* upgrade ubuntu version

* add purge method

* check

* delete test

* format check

* check2

* sync radixtree

* check operating radixtree

* change header

* common func

* fix upstream req

* calculate method bit in common function

* leave two blank lines between functions.

* erase blank line in test file

.github/workflows/test.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   test:
-    runs-on: "ubuntu-18.04"
+    runs-on: "ubuntu-20.04"
     env:
       OPENRESTY_PREFIX: "/usr/local/openresty"