Related to #43660
This patch reduces the unwanted offset&ts entries having same timestamp
of delete record. Under large amount of upsert, this false hit could
increase large amount of memory usage while applying delete.
The next step could be passing a callback to `search_pk_func_` to handle
hit entry streamingly.
Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>