tikvclient: fix a bug that recreate connection forever

[hicqu]

What problem does this PR solve?

When TiDB trys to re-create the connection to one TiKV, it just checks itself is shutdown or not for the first time. After that TiDB will keep retry if the re-create always fail.

What is changed and how it works?

With this PR TiDB will check it's shutdown or not for every retry, so it can exit successfully.

[codecov]

Codecov Report

Merging #10301 into master will decrease coverage by 0.0235%.
The diff coverage is 0%.

@@               Coverage Diff                @@
##             master     #10301        +/-   ##
================================================
- Coverage   77.8087%   77.7852%   -0.0236%     
================================================
  Files           410        410                
  Lines         84966      84930        -36     
================================================
- Hits          66111      66063        -48     
- Misses        13909      13917         +8     
- Partials       4946       4950         +4

[codecov]

Codecov Report

Merging #10301 into master will decrease coverage by 0.0106%.
The diff coverage is 0%.

@@               Coverage Diff                @@
##             master     #10301        +/-   ##
================================================
- Coverage   77.6681%   77.6575%   -0.0107%     
================================================
  Files           411        411                
  Lines         85452      85447         -5     
================================================
- Hits          66369      66356        -13     
- Misses        14121      14127         +6     
- Partials       4962       4964         +2

[tiancaiamao]

LGTM
PTAL @lysu

[lysu]

LGMT

[lysu]

@hicqu maybe we can add target addr in this log to help know fail target address

logutil.Logger(context.Background()).Error("batchRecvLoop re-create streaming fail", zap.Error(err))

[lysu]

/run-all-tests