move zero lamport list out of per-account for loop

[jeffwashington]

Problem

Account index insertion is the bottleneck on startup time.

Summary of Changes

Move code out of the per-account loop.
Fixes #

[jeffwashington]

measurements show a 1% improvement. Not huge, but this code path is the limiting factor on startup time. Makes sense to move operations out of the critical path per-account loop as # accounts grows.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@d99b8f1). Click here to learn what that means.
The diff coverage is 87.4%.

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[sakridge]

This is removed by #17601 which is close to be ready to merged.