[fuchsia] Use sysconf to get number of processors

runtime/bin/run_vm_tests_fuchsia.cc

Index: runtime/bin/run_vm_tests_fuchsia.cc
diff --git a/runtime/bin/run_vm_tests_fuchsia.cc b/runtime/bin/run_vm_tests_fuchsia.cc
index fddba5e0b4920d61b2ad1de9b2eddb5a15e565a4..e98837a936b70194bf53d8131e6795b04b14b4d3 100644
--- a/runtime/bin/run_vm_tests_fuchsia.cc
+++ b/runtime/bin/run_vm_tests_fuchsia.cc
@@ -7,7 +7,6 @@
 #include <magenta/syscalls.h>
 #include <mxio/util.h>
 #include <pthread.h>
-#include <runtime/sysinfo.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -305,7 +304,7 @@ int main(int argc, char** argv) {
   args.test_list_length = lines_count;
   args.test_list_index = &test_list_index;
 
-  const intptr_t num_cpus = mxr_get_nprocs_conf();
+  const intptr_t num_cpus = sysconf(_SC_NPROCESSORS_CONF);
   pthread_t* threads =
     reinterpret_cast<pthread_t*>(malloc(num_cpus * sizeof(pthread_t)));
   for (int i = 0; i < num_cpus; i++) {