Update to the new PA_HND-style processargs names

Change-Id: Ifeb862d93b8b7bed6091def6ae4a739eebabb4fe
diff --git a/benchmarks/spec_fixture.cc b/benchmarks/spec_fixture.cc
index ac24182..43d5e3b 100644
--- a/benchmarks/spec_fixture.cc
+++ b/benchmarks/spec_fixture.cc
@@ -161,7 +161,7 @@
                           mx_handle_t* process) {
   launchpad_t* lp = NULL;
   mx_handle_t job_to_child = MX_HANDLE_INVALID;
-  mx_handle_t job = mx_get_startup_handle(MX_HND_INFO(MX_HND_TYPE_JOB, 0));
+  mx_handle_t job = mx_get_startup_handle(PA_HND(PA_JOB_DEFAULT, 0));
   if (job != MX_HANDLE_INVALID) {
     mx_handle_duplicate(job, MX_RIGHT_SAME_RIGHTS, &job_to_child);
   }