Use const_eval instead of constant for more lints?

• eq_op won't join here because we expressly only want syntactically equal expressions
• bit_mask uses it
• float_cmp uses it
• approx_const doesn't even need constant because we only want to match literals
• zero_div_zero might probably be able to use it
• min_max might use it (but we currently bail on refs, so it's debatable whether it should)
• loops could benefit from it
• identity_op shouldn't use it because it bails on refs and it's so low-payoff that a full const_eval isn't worth it

What do you folks think?

Review the listed lints—eq_op, approx_const, zero_div_zero, min_max, identity_op, and loops—and compare their current use of constant with const_eval. Resolve which checklist items should change and confirm the accepted scope in the issue discussion; done means the selected lints consistently use the agreed approach.