Fixed incorrect comment wording for Iterator::Seek.
Add arm64 support to leveldb.
Added a new fault injection test.

This test is intended to ensure leveldb properly detects and recovers from
faults - specifically unwritten file data lost as a result of a system reset.
Clean up layering of storage/leveldb/...

With these changes, this package should be properly cleaned up and not require
any further changes.
Move header guard below copyright banner.
Add benchmark that measures cost of repeatedly opening the database.