Support: Drop LLVM_ATTRIBUTE_UNUSED_RESULT

Uses of this have all been updated to use LLVM_NODISCARD, which
matches the C++17 [[nodiscard]] semantics rather than those of GCC's
__attribute__((warn_unused_result)).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284367 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed