R4R: CollectStdTxs() must check DelegatorAddr against accounts

[alessio]

Closes: #3003

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.
• Wrote tests
• Updated relevant documentation (docs/)
• Added entries in PENDING.md with issue #
• 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 #3004 into develop will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #3004      +/-   ##
===========================================
- Coverage    55.53%   55.51%   -0.03%     
===========================================
  Files          120      120              
  Lines         8490     8490              
===========================================
- Hits          4715     4713       -2     
- Misses        3453     3455       +2     
  Partials       322      322

[alexanderbez]

Changes LGTM 👍

Not sure if this warrants a new test/test case.

[jackzampolin]

This looks great! good improvement @alessio. If there is a test case here could you add it too? Otherwise gets a 👍 from me!

[cwgoes]

Tested ACK, a testcase would be nice (maybe we should wait on the CLI testcase refactor though).