[clang-tools-extra] [clangd] Reduce instantiation depth in `infinite-instantiations.test` (PR #92888)

[Younan Zhang via cfe-commits]

https://github.com/zyn0217 approved this pull request.

Thanks! I added that test to check if the instantiation stack guard takes effect in clangd. And the change makes sense to me.

https://github.com/llvm/llvm-project/pull/92888