[Bug][compiler-v2] Compiler erroneously reports unused assignments in test

[alnoki]

@brmataptos @fEst1ck @georgemitenkov @gregnazario @rahxephon89 @runtian-zhou @vineethk @wrwg

Steps to reproduce

See this file snippet:
https://github.com/econia-labs/emojicoin-dot-fun/blob/4bae268f/src/move/emojicoin_arena/tests/tests.move#L1739-L1752

Then from in src/move/emojicoin_arena:

git ls-files | entr -c sh -c " \
       aptos move test --coverage --dev --move-2  &&
       aptos move fmt
   "

If I don't call the variables called out in the snippet, then the compiler erroneously reports an unused assignment even though it is used in the test:

warning: Unused assignment to `covered_unequal_market_ids`. Consider removing or prefixing with an underscore: `_covered_unequal_market_ids`
     ┌─ /Users/yours-truly/repos/emojicoin-dot-fun/src/move/emojicoin_arena/tests/tests.move:1741:42
     │
1741 │         let covered_unequal_market_ids = false;
     │   

However if I then delete the line, or prefix with _ as suggested, the compiler then reports:

error: undeclared `covered_unequal_market_ids`
     ┌─ /Users/yours-truly/repos/emojicoin-dot-fun/src/move/emojicoin_arena/tests/tests.move:1758:17
     │
1758 │                 covered_unequal_market_ids = true;
     │                 ^^^^^^^^^^^^^^^^^^^^^^^^^^

error: undeclared `covered_unequal_market_ids`
     ┌─ /Users/yours-truly/repos/emojicoin-dot-fun/src/move/emojicoin_arena/tests/tests.move:1783:17
     │
1783 │         assert!(covered_unequal_market_ids);
     │