test：update test case 

enh: refactor show variables

fix: handle rpc retry except

test: add test time count print

refactor(stream): seperate stream scheduling and persistence

test: redistribute vgroup

feat: alter local command

refactor(sync): add trace log

feat: sql command 'show consumers' and 'show subscriptions'

fix(wal): set first version to -1 if all log rollbacked

Test3.0/lihui

fix(query): math function invalid input should have null output

test: modify testcase of muti-mnodes

fix(stream): memory leak

enh: add stbinfo to minotor

refactor(sync): refactor wal abstraction