Change from "XFAIL: libcpp-no-exceptions" to "UNSUPPORTED: libcpp-no-exceptions" tests that only check exceptions and nothing else

This is a follow up of D24562.

These tests do not check anything but exceptions, so it makes sense to mark
them as UNSUPPORTED under a library built without exceptions.

Differential Revision: https://reviews.llvm.org/D26075



git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@285550 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/language.support/support.exception/uncaught/uncaught_exception.pass.cpp

@@ -7,7 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// XFAIL: libcpp-no-exceptions
+// UNSUPPORTED: libcpp-no-exceptions
 // test uncaught_exception
 
 #include <exception>