Fix CompactionIterator flag for penultimate level output (#10967)

Summary:
We were not resetting it in non-debug mode so it could be true once and then stay true for future keys where it should be false. This PR adds the reset logic.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10967

Test Plan:
- built `db_bench` with DEBUG_LEVEL=0
- ran benchmark: `TEST_TMPDIR=/dev/shm/prefix ./db_bench -benchmarks=fillrandom -compaction_style=1 -preserve_internal_time_seconds=100 -preclude_last_level_data_seconds=10 -write_buffer_size=1048576 -target_file_size_base=1048576 -subcompactions=8 -duration=120`
- compared "output_to_penultimate_level: X bytes + last: Y bytes" lines in LOG output
  - Before this fix, Y was always zero
  - After this fix, Y gradually increased throughout the benchmark

Reviewed By: riversand963

Differential Revision: D41417726

Pulled By: ajkr

fbshipit-source-id: ace1e9a289e751a5b0c2fbaa8addd4eda5525329

HISTORY.md

@@ -10,6 +10,7 @@
 * Fixed an issue where the `READ_NUM_MERGE_OPERANDS` ticker was not updated when the base key-value or tombstone was read from an SST file.
 * Fixed a memory safety bug when using a SecondaryCache with `block_cache_compressed`. `block_cache_compressed` no longer attempts to use SecondaryCache features.
 * Fixed a regression in scan for async_io. During seek, valid buffers were getting cleared causing a regression.
+* Tiered Storage: fixed excessive keys written to penultimate level in non-debug builds.
 
 ### New Features
 * Add basic support for user-defined timestamp to Merge (#10819).

db/compaction/compaction_iterator.cc

@@ -1105,7 +1105,9 @@ void CompactionIterator::DecideOutputLevel() {
   TEST_SYNC_POINT_CALLBACK("CompactionIterator::PrepareOutput.context",
                            &context);
   output_to_penultimate_level_ = context.output_to_penultimate_level;
-#endif /* !NDEBUG */
+#else
+  output_to_penultimate_level_ = false;
+#endif  // NDEBUG
 
   // if the key is newer than the cutoff sequence or within the earliest
   // snapshot, it should output to the penultimate level.