[test] Disable pthread_mutexattr_t.swift

Author: hamishknight

test/Interop/Cxx/objc-correctness/pthread_mutexattr_t.swift

@@ -1,6 +1,9 @@
 // RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -enable-objc-interop -enable-experimental-cxx-interop
 // REQUIRES: OS=macosx
 
+// Temporarily disable (rdar://128544755)
+// REQUIRES: rdar128544755
+
 import Darwin
 
 _ = pthread_mutexattr_t() // expected-warning {{'init()' is deprecated: This zero-initializes the backing memory of the struct}}