fix: nil pointer panic on NewIntFromBigInt (backport #9627)

[mergify]

This is an automatic backport of pull request #9627 done by Mergify.
Cherry-pick of 7f90374 has failed:

On branch mergify/bp/release/v0.43.x/pr-9627
Your branch is up to date with 'origin/release/v0.43.x'.

You are currently cherry-picking commit 7f9037490.
  (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:   types/int.go
	modified:   types/int_test.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   CHANGELOG.md

To fix up this pull request, you can check it out locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

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[amaury1093]

@fedekunze Could you fix the conflicts here?

[fedekunze]

@AmauryM done

[amaury1093]

thanks!

[amaury1093]

Feel free to approve yourself too. And then I can merge

[amaury1093]

It has been decided in #9634 that this is a protocol-breaking change, so I don't think we should backport it. Is this fine by you @fedekunze ?

[fedekunze]

sure