feat: add the ability to specifiy the txsim master account (backport #2292)

[mergify]

This is an automatic backport of pull request #2292 done by Mergify.
Cherry-pick of 2102189 has failed:

On branch mergify/bp/v1.x/pr-2292
Your branch is up to date with 'origin/v1.x'.

You are currently cherry-picking commit 2102189.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   app/test/square_size_test.go
	modified:   test/cmd/txsim/cli.go
	modified:   test/txsim/account.go
	modified:   test/txsim/run.go
	modified:   test/txsim/run_test.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   test/e2e/simple_test.go

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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[codecov-commenter]

Codecov Report

❗ No coverage uploaded for pull request base (v1.x@a93dc76). Click here to learn what that means.
The diff coverage is n/a.

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