Update comments, variable names and assertions on transfer test

[bugarela]

Hello

Description

I've been working a quint specification for ICS20 and, while writing a test based on the transfer_test.go test (progress here informalsystems/quint#874), I noticed some of the comments were outdated. Seems like the test was updated to include additional transfer steps, but the comments were not.

This PR:

1. Updates those comments
2. Renames path into pathAtoB so it works best along with the existing variable named pathBtoC
3. Adds an assertion on the balance of chain A at the end (based on outdated comments, felt like this was suppose to be checked)
4. Changes the test on the escrow account to check the denom that was previously in the escrow account, not the default denom. I think this makes more sense than checking for a denom that was never in the escrow account in the first place.

• PS: I was not able to check that the escrow account actually has any tokens when it is suppose to. I don't know if I'm doing something wrong or if there is something in the test setup that prevents escrow accounts from being updated.

Commit Message / Changelog Entry

test: update comments, variable names and assertions on transfer test

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[crodriguezvega]

Thanks for these improvement, @bugarela! I added an extra check for the escrow account on chain A. I think one comment needs to be updated, since the balance on sender account on chain A will not be empty, but besides that, the changes look good to me! 👍

[damiannolan]

Thank you @bugarela 🙏