Tuple CTAD is failing with NVCC + GCC and NVCC + Clang

[brycelelbach]

In internal CI, we're seeing failures of some tuple CTAD tests with NVCC + GCC and NVCC + Clang.

Clang 8 (the only C++17 Clang in CI) fails:

std/utilities/tuple/tuple.tuple/tuple.cnstr/deduct.pass.cpp
std/utilities/utility/pairs/pairs.pair/implicit_deduction_guides.pass.cpp

GCC 8 and GCC 9 fail:

std/utilities/tuple/tuple.tuple/tuple.cnstr/deduct.pass.cpp

I'm not certain which of these host compilers NVCC actually supports in C++17 mode; perhaps that's part of the issue.

I'm planning to XFAIL the tests in #97, at least for the time being.

[brycelelbach]

This is looking like a compiler bug that's going to need creduce.

[wmaxey]

Closing, I believe this has been fixed.