The tests for unordered_set and unordered_multiset were missing UNSUPPORTED
markup for Apple Clang 9.1, which is still being used on some CI bots.
llvm-svn: 366259
// <unordered_set>
// UNSUPPORTED: c++98, c++03, c++11, c++14
// UNSUPPORTED: libcpp-no-deduction-guides
+// UNSUPPORTED: apple-clang-9.1
// template<class InputIterator,
// class Hash = hash<iter-value-type<InputIterator>>,
// <unordered_set>
// UNSUPPORTED: c++98, c++03, c++11, c++14
// UNSUPPORTED: libcpp-no-deduction-guides
+// UNSUPPORTED: apple-clang-9.1
// template<class InputIterator,
// class Hash = hash<iter-value-type<InputIterator>>,