Fix Failed Simulation Seeds

[alexanderbez]

• Fixes a hang where only one account is generated
• Fixes the situation where a vesting account's end time and start time are the same

closes: #4139

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• Targeted PR against correct branch (see CONTRIBUTING.md)

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.

• Wrote tests

• Updated relevant documentation (docs/)

• Added a relevant changelog entry: sdkch add [section] [stanza] [message]

• rereviewed Files changed in the github PR explorer

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For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
• Reviewers Assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[codecov]

Codecov Report

Merging #4140 into develop will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           develop   #4140      +/-   ##
==========================================
+ Coverage    60.18%   60.2%   +0.02%     
==========================================
  Files          212     212              
  Lines        15157   15157              
==========================================
+ Hits          9122    9126       +4     
+ Misses        5411    5407       -4     
  Partials       624     624

[alexanderbez]

I am stumped as to why test_sim_gaia_simulation_after_import consistently fails. It passes for me locally and passes for me on Zaki's megabox. I've noticed this on other PRs too; after eventually enough retries it passes. I don't think this is non-determinism, but something to do with the script or the OS.

[cwgoes]

ACK