[llvm] Extend GCC workaround to GCC < 8.4 for llvm::iterator_range ctor (PR #82643)

[Thomas Preud'homme via llvm-commits]

RoboTux wrote:

Nope sorry, it fixed one issue but there are more cases of decltype involved in SFINAE and it's hard to fix all of them. The current patch works for some users of MLIR at least, though clearly not all of them since building all of MLIR doesn't.

If people don't mind I'd like to keep the current patch in while we support GCC 8 because it helps my usecase and doesn't break any build not already broken (if it does I'm happy to revert it myself).

https://github.com/llvm/llvm-project/pull/82643