[XRay] Mark default-options.cpp unsupported on ppc

This test fails now that it actually runs:

ld.lld: error: undefined symbol: std::__throw_system_error(int)

Author: boomanaiden154

compiler-rt/test/xray/TestCases/Posix/default-options.cpp

@@ -4,6 +4,8 @@
 
 // REQUIRES: built-in-llvm-tree
 
+// UNSUPPORTED: ppc
+
 extern "C" __attribute__((xray_never_instrument)) const char *
 __xray_default_options() {
   return "patch_premain=true:verbosity=1:xray_mode=xray-basic";