Signed-off-by: Azat Khuzhin <[email protected]>

getAlterMutationCommandsForPart() can be a hot path for query execution
when there are pending mutations.

- LOG_TEST - it is not only check one bool, but actually a bunch of
  atomics as well.

- Return std::vector over std::map (map is not required there) - no
  changes in performance.

- Copy only RENAME_COLUMN (since only this mutation is required by
  AlterConversions).

And here are results:

run|result
-|-
SELECT w/o ALTER|queries: 1565, QPS: 355.259, RPS: 355.259
SELECT w/ ALTER unpatched|queries: 2099, QPS: 220.623, RPS: 220.623
SELECT w/ ALTER and w/o LOG_TEST|queries: 2730, QPS: 235.859, RPS: 235.859
SELECT w/ ALTER and w/o LOG_TEST and w/ RENAME_COLUMN only|queries: 2995, QPS: 290.982, RPS: 290.982

But there are still room for improvements, at least MergeTree engines
could implement getStorageSnapshotForQuery().

Signed-off-by: Azat Khuzhin <[email protected]>

…ector<MutationCommand>>

* u/pr/60139:
  Fix data race

* u/pr/59531:
  Work around what appears to be a clang static analysis bug
  Add AlterConversions::supportsMutationCommandType(), flatten vector<vector<MutationCommand>>
  Improve performance of SELECTs with active mutations
  Configure keeper for perf tests

* u/pr/60041:
  Fixed build
  Updated implementation
  PartsSplitter invalid ranges for the same part