REUSABLE_DATA memory mode creates duplicate aggregator handles in DELTA temporalit

https://github.com/open-telemetry/opentelemetry-java/blob/e6b9462f24410ae9d5b1a3717624122c7709640c/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/state/DefaultSynchronousMetricStorage.java#L219-L323

In DefaultSynchronousMetricStorage, when using MemoryMode.REUSABLE_DATA with AggregationTemporality.DELTA, the implementation maintains two aggregator handles per unique attribute set due to a ping-pong pattern between collection intervals.

During the collection operation, a new aggregatorHolder is created with the handles from previousCollectionAggregatorHandles. In any case, when an instrument is registered for the first time, it will not be present in the previousCollectionAggregatorHandles. So, for the next collection cycle, another duplicate handle is created for the same. Throughout the lifetime of the application, both of these objects coexist, causing an increased memory footprint in the storage. For instruments with multiple tags, this becomes a memory overhead.

One thing I could probably think of is probably hold writelock for a few more instructions for DELTA and REUSABLE_DATA, and reuse the existing handle by only resetting the values. We can also improve the attribute reset behaviour (cardinality control) in this mode to remove only those instruments that are not recorded in the last interval.

Start in sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/state/DefaultSynchronousMetricStorage.java, especially lines 219-323, and trace aggregatorHolder creation across DELTA collection intervals. Compare the previousCollectionAggregatorHandles flow with REUSABLE_DATA behavior. Done means each unique attribute set does not retain duplicate aggregator handles while preserving collection and cardinality behavior.