Summary:
Improve test coverage. Also these are essential to C++ code.

Fixed one asan bug where misaligned pointer access.

Test Plan: Jenkins test.

Reviewers: #engineering, oazizi, zasgar, chengruizhe

Reviewed By: #engineering, zasgar

Differential Revision: https://phab.corp.pixielabs.ai/D1024

GitOrigin-RevId: ed640ca0724ddc5e3ac1845fd7be7b61c2928240