[llvm] [NFC][TableGen] Print topmost def location for Intrinsics/Insts (PR #160796)

[Jay Foad via llvm-commits]

jayfoad wrote:

It's not at all clear to me that this is better when there are multiple levels of multiclasses involved. Drilling down the defm hierarchy can involve just as much guesswork as drilling "up". C++ compilers tend to print the whole stack of locations, for analogous situations like nested template instantiations.

https://github.com/llvm/llvm-project/pull/160796