Stop using deprecated (names of) magenta syscalls.

runtime/vm/virtual_memory_fuchsia.cc

Index: runtime/vm/virtual_memory_fuchsia.cc
diff --git a/runtime/vm/virtual_memory_fuchsia.cc b/runtime/vm/virtual_memory_fuchsia.cc
index b7b8b891d99326a064aa2233258967e7cf257b5c..8cbc836fd8724c0c198189b4ad5b368b89625dfd 100644
--- a/runtime/vm/virtual_memory_fuchsia.cc
+++ b/runtime/vm/virtual_memory_fuchsia.cc
@@ -26,7 +26,7 @@ void VirtualMemory::InitOnce() {
 
 
 VirtualMemory* VirtualMemory::ReserveInternal(intptr_t size) {
-  mx_handle_t vmo = mx_vm_object_create(size);
+  mx_handle_t vmo = mx_vmo_create(size);
   if (vmo <= 0) {
     return NULL;
   }