Fix __uuidof handling on non-type template parameter in C++17

Clang used to pass the base lvalue of a non-type template parameter
to the template instantiation phase when the base part is __uuidof
and it's running in C++17 mode.
However, that drops its LValuePath, and unintentionally transforms
&__uuidof(...) to __uuidof(...).

This CL fixes that by passing whole expr. Fixes PR24986.

https://reviews.llvm.org/D46820?id=146557
Patch from Taiju Tsuiki <tzik@chromium.org>!

llvm-svn: 332614