Minor client output buffer optimizations (#8699)
Minor client output buffer optimizations (#8699)

* Avoid checking output limits if buffer didn't grow.
* Use previouse node in case it has room in deferred output node.
PKRoma/redis,charsyam/redis,neomantra/redis,antirez/redis,antirez/redis,ctripcorp/redis,soloestoy/redis,yossigo/redis,charsyam/redis,yossigo/redis,PKRoma/redis,yossigo/redis,yossigo/redis,ofirluzon/redis,neomantra/redis,charsyam/redis,ctripcorp/redis,ofirluzon/redis,soloestoy/redis,charsyam/redis,neomantra/redis,PKRoma/redis,antirez/redis,ofirluzon/redis,yossigo/redis,oranagra/redis,ctripcorp/redis,PKRoma/redis,neomantra/redis,ofirluzon/redis,antirez/redis,PKRoma/redis,neomantra/redis,oranagra/redis,oranagra/redis,oranagra/redis,soloestoy/redis,soloestoy/redis,oranagra/redis,ofirluzon/redis,charsyam/redis,soloestoy/redis,ctripcorp/redis