feat: prefetch more trie keys

[Longarithm]

[mooori]

Could the keys accessed via ft_balance_of be prefetched as well? Such access was quite frequent in Cosmose unit tests, though I don't know how relevant they are for mainnet traffic.

[Longarithm]

Ah. I suspect ft_balance_of is a read-only query, and these ones are served from FlatStorage, which is only 1 fast disk read. Only write queries matter.

Note: with stateless validation everything will be served from memtrie in memory, so hopefully this hack is a short-term. We consider enabling memtries even sooner.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 42.04545% with 102 lines in your changes are missing coverage. Please review.

Project coverage is 71.44%. Comparing base (57ff810) to head (964bb71).

Files	Patch %	Lines
runtime/runtime/src/prefetch.rs	31.75%	93 Missing and 8 partials :warning:
core/store/src/trie/config.rs	90.00%	1 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #10899      +/-   ##
==========================================
- Coverage   71.49%   71.44%   -0.06%     
==========================================
  Files         759      759              
  Lines      152522   152594      +72     
  Branches   152522   152594      +72     
==========================================
- Hits       109042   109015      -27     
- Misses      38964    39051      +87     
- Partials     4516     4528      +12     

Flag	Coverage Δ
backward-compatibility	0.24% <0.00%> (-0.01%)	:arrow_down:
db-migration	0.24% <0.00%> (-0.01%)	:arrow_down:
genesis-check	1.43% <5.74%> (+<0.01%)	:arrow_up:
integration-tests	37.12% <21.02%> (-0.06%)	:arrow_down:
linux	69.92% <41.47%> (-0.02%)	:arrow_down:
linux-nightly	70.89% <42.04%> (-0.07%)	:arrow_down:
macos	54.46% <32.95%> (-0.04%)	:arrow_down:
pytests	1.65% <5.74%> (+<0.01%)	:arrow_up:
sanity-checks	1.44% <5.74%> (+<0.01%)	:arrow_up:
unittests	67.07% <41.47%> (-0.05%)	:arrow_down:
upgradability	0.29% <0.00%> (-0.01%)	:arrow_down:

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[wacban]

Also do we have any good metrics and logs for prefetcher? If not can you add those and prepare a dashboard?

[bowenwang1996]

@Longarithm could we merge this PR :)

[nagisa]

FWIW we can look and keep an eye on the prefetching graphs to get some intuition as to whether the prefetcher is working as we intend it to. But also, we should merge this sooner rather than later? We've a release pending soon and if my memory serves me right we wanted this PR in it?

cc @VanBarbascu

[Longarithm]

Addressed most comments, prioritising getting this into next release. Had some trouble with merging with prefetching logic on master but came through it.