Remove two ABI symbols added after the 3.9 release

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@284200 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/string b/include/string
index 3ffe74d..b56ab38 100644
--- a/include/string
+++ b/include/string
@@ -1174,6 +1174,7 @@
     int compare(size_type __pos1, size_type __n1, const basic_string& __str) const;
     int compare(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2=npos) const;
     template <class _Tp>
+    inline _LIBCPP_INLINE_VISIBILITY
         typename enable_if
         <
             __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,