fix: clippy warnings

sbroad-core/src/backend/sql/ir/tests.rs

sbroad-core/src/backend/sql/ir/tests/except.rs

sbroad-core/src/backend/sql/space.rs

sbroad-core/src/backend/sql/tree/tests.rs

sbroad-core/src/executor/engine/helpers/vshard.rs

sbroad-core/src/executor/ir.rs

sbroad-core/src/frontend/sql/ir.rs

sbroad-core/src/ir.rs

sbroad-core/src/ir/node.rs

sbroad-core/src/ir/node/acl.rs

sbroad-core/src/ir/node/block.rs

sbroad-core/src/ir/node/ddl.rs

sbroad-core/src/ir/node/expression.rs

sbroad-core/src/ir/node/relational.rs

sbroad-core/src/ir/node/tests.rs

sbroad-core/src/ir/node/util.rs

sbroad-core/src/ir/operator.rs

sbroad-core/src/ir/transformation/helpers.rs