[libc++][z/OS] Switch to use TEST_HAS_NO_INT128 as per comment in PR 92261 (#92434)

Follow up to #92261.

Author: zibi2

libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/assign.pass.cpp

@@ -84,12 +84,12 @@ int main(int, char**)
     test_ext<unsigned int>();
     test<unsigned long>();
     // This isn't implemented on platforms without __int128
-#ifndef _LIBCPP_HAS_NO_INT128
+#ifndef TEST_HAS_NO_INT128
     test_ext<unsigned long>();
 #endif
     test<unsigned long long>();
     // This isn't implemented on platforms without __int128
-#ifndef _LIBCPP_HAS_NO_INT128
+#ifndef TEST_HAS_NO_INT128
     test_ext<unsigned long long>();
 #endif
 

libcxx/test/std/numerics/rand/rand.eng/rand.eng.lcong/copy.pass.cpp

@@ -83,12 +83,12 @@ int main(int, char**)
     test_ext<unsigned int>();
     test<unsigned long>();
     // This isn't implemented on platforms without __int128
-#ifndef _LIBCPP_HAS_NO_INT128
+#ifndef TEST_HAS_NO_INT128
     test_ext<unsigned long>();
 #endif
     test<unsigned long long>();
     // This isn't implemented on platforms without __int128
-#ifndef _LIBCPP_HAS_NO_INT128
+#ifndef TEST_HAS_NO_INT128
     test_ext<unsigned long long>();
 #endif