use seqlock for AccountStorage count and status tracking

[HaoranYi]

Problem

count_and_status are a tuple, which implement Copy traits. This make it
a good candiate to use light-weight SeqLock instead of RwLock.

similar to #33696

Summary of Changes

Use seqlock for count and status for AccountStorageEntry tracking.

Fixes #

[codecov]

Codecov Report

Merging #34356 (ea92201) into master (fa25176) will increase coverage by 0.0%.
Report is 14 commits behind head on master.
The diff coverage is 86.6%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #34356   +/-   ##
=======================================
  Coverage    81.9%    81.9%           
=======================================
  Files         819      819           
  Lines      220422   220422           
=======================================
+ Hits       180673   180699   +26     
+ Misses      39749    39723   -26     

[brooksprumo]

Looks good to me. I looked through the code at all the places that use count_and_status to see if there's anything going on that may've been fishy and required an RwLock. It all looked clear to me.

Good find!