Fix the unstable test TestWagedNodeSwap.

[jiajunwang]

Issues

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Fixes #1737

Description

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The original verifier may not check every DB before returns. This fails the following test cases occasionally.
This PR fixed the verifier. It also adds some randomize to the test.

Tests

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Pure test fix for TestWagedNodeSwap.

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Code Quality

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[jiajunwang]

Approved by @alirezazamani , ready to me merged.