Proto/test/token: test total supply update

What

Fix #5653 (closed)

Add total supply checks in the tests in test_token. Most importantly, the test all is covered.

Why

More tests :)

How

Add a check for the total supply after each call to transfer in test_token.ml. Some transfers are expected to fail, so we don't need to check those.

For transfer_n, we do not check for each transfer, but the current test checks that transfer_n is similar to "n" transfers, so we just need to check that the total supply is the same either way.

Manually testing the MR

dune exec src/proto_alpha/lib_protocol/test/integration/main.exe -- --file test_token.ml

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR