Summary:
* Add some options to cache_bench to use JemallocNodumpAllocator
* Make num_shard_bits option use and report cache-specific defaults
* Add a usleep option to sleep between operations, for simulating a workload with more CPU idle/wait time.
* Use const& for JemallocAllocatorOptions, to improve API usability (e.g. can bind to temporary `{}`)
* InstallStackTraceHandler()

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11758

Test Plan: manual

Reviewed By: jowlyzhang

Differential Revision: D48668479

Pulled By: pdillinger

fbshipit-source-id: b6032fbe09444cdb8f1443a5e017d2eea4f6205a