Mark CTAD fail tests for set/multiset as XFAIL for older compilers that give different error messages

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@363099 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/std/containers/associative/multiset/multiset.cons/deduct.fail.cpp b/test/std/containers/associative/multiset/multiset.cons/deduct.fail.cpp
index 3b5b0db..ff81a20 100644
--- a/test/std/containers/associative/multiset/multiset.cons/deduct.fail.cpp
+++ b/test/std/containers/associative/multiset/multiset.cons/deduct.fail.cpp
@@ -9,6 +9,8 @@
 // <set>
 // UNSUPPORTED: c++98, c++03, c++11, c++14
 // UNSUPPORTED: libcpp-no-deduction-guides
+// XFAIL: clang-6, apple-clang-9.0, apple-clang-9.1
+//  clang-6 gives different error messages.
 
 // template<class InputIterator,
 //          class Compare = less<iter-value-type<InputIterator>>,
diff --git a/test/std/containers/associative/set/set.cons/deduct.fail.cpp b/test/std/containers/associative/set/set.cons/deduct.fail.cpp
index 861339b..3731205 100644
--- a/test/std/containers/associative/set/set.cons/deduct.fail.cpp
+++ b/test/std/containers/associative/set/set.cons/deduct.fail.cpp
@@ -9,6 +9,8 @@
 // <set>
 // UNSUPPORTED: c++98, c++03, c++11, c++14
 // UNSUPPORTED: libcpp-no-deduction-guides
+// XFAIL: clang-6, apple-clang-9.0, apple-clang-9.1
+//  clang-6 gives different error messages.
 
 // template<class InputIterator,
 //          class Compare = less<iter-value-type<InputIterator>>,