[clang] [AST] Assert that FoldingSetNodeID used for hint is correct upon insertion (PR #157692)

[Erich Keane via cfe-commits]

erichkeane wrote:

What if we replace the calls to `insertNode` with a helper function macro instead?  So:

`InsertNode(VectorTypes, ID, New, InsertPos);`

Which is then:
`#define InsertNode(Ty, ID, Elt, Pos) assert(<call to helper>);Ty.InsertNode(Ty, Pos);`

Sensible?  Or presumably we can have an always-inline function wrapper for that, and the inliner will just take care of it.

https://github.com/llvm/llvm-project/pull/157692