Improve scheduling in account-based migration

[turbolent]

Depends on #5897

Closes onflow/cadence#3308

Currently, the migrations of accounts are scheduled in address order. If there are large accounts at high addresses, the migration might end up waiting for a these accounts, with most available workers idling.

Schedule the migration of large accounts first to increase utilization of available workers.

[SupunS]

Good idea!

[fxamacker]

Nice!

I only left a suggestion about avoiding overhead of creating and sorting allAccountRegisters slice by only tracking the largest accounts above a threshold.

[turbolent]

@fxamacker @SupunS PTAL at the improved version which does not sort: https://github.com/onflow/flow-go/pull/5901/files/53fe9a69d901d7c15846a6a2cc8879c08f122c82..bdba7af3eb1daf165ca8b2fee86cc2a43f75c162

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 80.00000% with 20 lines in your changes are missing coverage. Please review.

Project coverage is 55.61%. Comparing base (15d2e63) to head (db1b024).
Report is 181 commits behind head on master.

Files	Patch %	Lines
...ledger/migrations/account_size_filter_migration.go	0.00%	11 Missing ⚠️
.../util/ledger/migrations/account_based_migration.go	84.21%	7 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5901      +/-   ##
==========================================
+ Coverage   55.58%   55.61%   +0.02%     
==========================================
  Files        1127     1128       +1     
  Lines       88840    88926      +86     
==========================================
+ Hits        49380    49453      +73     
- Misses      34751    34761      +10     
- Partials     4709     4712       +3     

Flag	Coverage Δ
unittests	55.61% <80.00%> (+0.02%)	⬆️

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[fxamacker]

Nice! Thanks for updating PR to replace very large sorted slice with a tiny queue!

I only left 1 comment about Less() for topDurations.