Add more assertions for cluster(distribution) mode

**Is your feature request related to a problem? Please describe.**

In cluster mode, performing the Last join query without index optimization (enable_distsql=true) is not allowable. So, the engine should throw a compile error when we turn on enable_distsql instead of running with wrong results.

This issue is going to add more assertions in cluster mode to avoid bugs like #612

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Look at issue #612 for context on the bug. The work involves adding assertions in cluster mode, likely in the query compiler or planner when enable_distsql is true. Search for 'enable_distsql' and 'Last join' in the codebase to find relevant files. The goal is to throw a compile error instead of producing wrong results. Run existing tests related to cluster mode and distsql to ensure the new assertions work.

Written by the indexing model from the issue text.