executor: fix unexpected mpp grpc EOF error log

[guo-shaoge]

What problem does this PR solve?

Issue Number: close #50011

Problem Summary: introduced by https://github.com/pingcap/tidb/pull/49401/files#diff-bb7331df1642b992efeb5699402d591f45fbc8b9baec6c024680156ae3a5656aR522

What changed and how does it work?

EOF error of grpc stream Recv() indicates a stream completes successfully, ref: https://github.com/grpc/grpc-go/blob/master/stream.go#L134

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No need to test

  • I checked and no code files have been changed.

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[codecov]

Codecov Report

Merging #50010 (7632681) into master (37c7326) will decrease coverage by 3.1182%.
Report is 8 commits behind head on master.
The diff coverage is 0.0000%.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #50010        +/-   ##
================================================
- Coverage   71.9115%   68.7933%   -3.1182%     
================================================
  Files          1438       1440         +2     
  Lines        345747     408596     +62849     
================================================
+ Hits         248632     281087     +32455     
- Misses        76855     108507     +31652     
+ Partials      20260      19002      -1258     

Flag	Coverage Δ
integration	44.1167% <0.0000%> (?)
unit	71.9680% <ø> (+0.0565%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	56.3129% <ø> (ø)
parser	∅ <ø> (∅)
br	43.9659% <ø> (-7.6422%)	⬇️

[windtalker]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: windtalker, wshwsh12

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-01-03 06:13:59.651113172 +0000 UTC m=+2237530.688340094: ☑️ agreed by wshwsh12.
• 2024-01-03 06:27:47.165990739 +0000 UTC m=+2238358.203217667: ☑️ agreed by windtalker.