feat: tuning the locator algorithm

[driftluo]

What problem does this PR solve?

This previous PR #3261 increased the locator length, but it didn't solve the problem

Take the current height as an example：
Current Algorithm：
[8480818...8480809, 8480807 ...4286507, 92203, 46101, 23050, 11525, 5762]
PR Algorithm：
[8480818...8480809, 8480807 ...4286507, 2143253, 1071626, 535813, 267906, 133953, 66976, 33488, 16744, 8372, 4186]

At the moment index < step * 2, too much data is skipped. This will cause a break in the download process, resulting in ibd not being able to be in a multi-node download state as much as possible.

What we want to do is, at the moment index < step * 2, turn on the right-shift decrement of the index directly, so that the data is not broken as much as possible

ref: #3668

Check List

Tests

• Unit test
• Integration test

Release note

Title Only: Include only the PR title in the release note.

[driftluo]

bors r+

[bors]

Build succeeded:

• ci_benchmarks_ubuntu
• ci_cargo_deny_ubuntu
• ci_integration_tests_ubuntu
• ci_linters_ubuntu
• ci_quick_checks_ubuntu
• ci_unit_tests_ubuntu
• ci_wasm_build_ubuntu