Enable native vpython on findit bucket's builders.

R=iannucci,tandrii

No-Try: True
Bug: 795146
Change-Id: Ib19e24035fcf46d3563ece2eda7271bc1e176a03
Reviewed-on: https://chromium-review.googlesource.com/1100174
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567059}

infra/config/global/cr-buildbucket.cfg

@@ -2237,6 +2237,7 @@ buckets {
       dimensions: "pool:luci.chromium.findit"
       service_account: "findit-builder@chops-service-accounts.iam.gserviceaccount.com"
       execution_timeout_secs: 28800  # 8h
+      swarming_tags: "vpython:native-python-wrapper"
       build_numbers: YES
       caches {
         path: "win_toolchain"