[APFloatTest] Use std::make_tuple to make GCC 4.8 happy

Differential Revision: https://reviews.llvm.org/D26817

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289474 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed