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Summary

1. Move cte context from Binder to BindContext to make materialized cte used in subquery(Subquery will use a new Binder to bind it, if cte context is in Binder, it isn't convenient to make the main query wrap m cte).
2. Remove m_cte_bound_ctx and used_count, they're not necessary to maintain.

After refactoring, the cte-related code is more maintainable and extensible.

• fixes: bug: materialized cte panic #16778

Tests

• Unit Test
• Logic Test
• Benchmark Test
• No Test - Explain why

Type of change

• Bug Fix (non-breaking change which fixes an issue)
• New Feature (non-breaking change which adds functionality)
• Breaking Change (fix or feature that could cause existing functionality not to work as expected)
• Documentation Update
• Refactoring
• Performance Improvement
• Other (please describe):

This change is