[sanitizer] zx_vmo_write on Fuchsia takes only 4 arguments now

[phosek]

Summary

The system call now fails when it cannot write the requested size.
Update the sanitizer runtime Fuchsia implementation accordingly.

[mcgrathr]

Lgtm

compiler-rt/lib/sanitizer_common/sanitizer_fuchsia.cc

void DumpProcessMap() {
   return;
 }
 
 bool IsAccessibleMemoryRange(uptr beg, uptr size) {
   // TODO(mcgrathr): Figure out a better way.
   zx_handle_t vmo;
   zx_status_t status = _zx_vmo_create(size, 0, &vmo);
   if (status == ZX_OK) {
-    while (size > 0) {
-      size_t wrote;
-      status = _zx_vmo_write(vmo, reinterpret_cast<const void *>(beg), 0, size,
-                             &wrote);
-      if (status != ZX_OK) break;
-      CHECK_GT(wrote, 0);
-      CHECK_LE(wrote, size);
-      beg += wrote;
-      size -= wrote;
-    }
+    status = _zx_vmo_write(vmo, reinterpret_cast<const void *>(beg), 0, size);
     _zx_handle_close(vmo);
   }
   return status == ZX_OK;
 }
 
 // FIXME implement on this platform.
 void GetMemoryProfile(fill_profile_f cb, uptr *stats, uptr stats_size) {}