Automatic merge from submit-queue (batch tested with PRs 50381, 51307, 49645, 50995, 51523)
Bugfix: Use local JSON log buffer in parseDockerJSONLog.
**What this PR does / why we need it**:
The issue described in #47800 is due to a race condition in `ReadLogs`: Because the JSON log buffer (`dockerJSONLog`) is package-scoped, any two goroutines modifying the buffer could race and overwrite the other's changes. In particular, one goroutine could unmarshal a JSON log line into the buffer, then another goroutine could `Reset()` the buffer, and the resulting `Stream` would be empty (`""`). This empty `Stream` is caught in a `case` block and raises an `unexpected stream type` error.
This PR creates a new buffer for each execution of `parseDockerJSONLog`, so each goroutine is guaranteed to have a local instance of the buffer.
**Which issue this PR fixes**: fixes#47800
**Release note**:
```release-note
Fixed an issue (#47800) where `kubectl logs -f` failed with `unexpected stream type ""`.
```
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