[mlir][Symbol] Add verification that symbol's parent is a SymbolTable (#80590)

Following the discussion in
https://discourse.llvm.org/t/symboltable-and-symbol-parent-child-relationship/75446

,
we should enforce that a symbol's immediate parent is a symbol table.

I changed some tests to pass the verification. In most cases, we can
wrap the func with a module, change the func to another op with regions
i.e. scf.if, or change the expected error message.

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Co-authored-by: Mehdi Amini <joker.eph@gmail.com>