Make `HirEqInterExpr::eq_block` take comments into account while checking if two blocks are equal
This PR:
- now makes `HirEqInterExpr::eq_block` take comments into account. Identical code with varying comments will no longer be considered equal.
- makes necessary adjustments to UI tests.
Closes#12044
**Lintcheck Changes**
- `match_same_arms` 53 => 52
- `if_same_then_else` 3 => 0
changelog: [`if_same_then_else`]: Blocks with different comments will no longer trigger this lint.
changelog: [`match_same_arms`]: Arms with different comments will no longer trigger this lint.
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