Update missing-owner-check lint to ignore if the key of the account is compared

[S3v3ru5]

The PR updates the lint to check if key of account is compared against some value. if the key is compared then the account is ignored by the lint and is not reported.

The update to the lint is as follows:

Given list of account_expr where each account_expr returns AccountInfo

1. For each account_expr
2. Walk through each expression in the body of the function
3. Check if the expression is a comparison: == or !=
4. Check if lhs or rhs of the comparison accesses the key on the account_expr
   • The key could be accessed using .key() for Anchor and .key for Solana AccountInfo.
   • Check if the expression is a method call to .key() or is a field access expression accessing .key.

The PR also makes some of the functions generic and removes redundant code.

[smoelius]

I have one style nit. I think(?) before this PR the functions were topologically sorted from "callers" to "callees". Would it possible to preserve that?

So, for example, could compares_key appear before expr_accesses_key which appears before uses_given_field?

(Apologies if there is a cycle I am not seeing.)

[S3v3ru5]

Update the lint. I wondered why the code was easy to follow. Will be sure to follow the style.

[smoelius]

Beautiful.