Reland "Reland "Send spec_name tags to event mon metrics""
Reland "Reland "Send spec_name tags to event mon metrics""

This is a reland of 47e502ce856c497c1c533af1feb9f1cc6ee00a08

I've tested this on staging, and it hasn't errored yet like it did in
the past. I've landed a CL to fix the proto in swarming in
https://crrev.com/c/1184118.

Original change's description:
> Reland "Send spec_name tags to event mon metrics"
>
> This is a reland of 1468930eae836a574f8937daa7cf704db24b3de7
>
> Added the field to the proto, which was rolled into luci-py. This should
> work now. I'll test before deploying to prod.
>
> Original change's description:
> > Send spec_name tags to event mon metrics
> >
> > Change-Id: I1ce5c1529da97b9f3ca15ccf337406f6dae41ae2
> > Reviewed-on: https://chromium-review.googlesource.com/1098385
> > Reviewed-by: Marc-Antoine Ruel <maruel@chromium.org>
> > Commit-Queue: Stephen Martinis <f3fbe4c4218d2421400bf0bd07366865fd7a0c7e@chromium.org>
>
> Change-Id: I817629ccdc3bc453e97928f4e9e9160da5b498bd
> Reviewed-on: https://chromium-review.googlesource.com/1155684
> Reviewed-by: Marc-Antoine Ruel <maruel@chromium.org>
> Commit-Queue: Marc-Antoine Ruel <maruel@chromium.org>

Change-Id: Ibbc62705055ab783aeab263cc3c3db60c9fcad1b
Reviewed-on: https://chromium-review.googlesource.com/1182261
Reviewed-by: smut <95deb7aa15d4c615299e47e7688551456568b1fb@google.com>
Commit-Queue: Stephen Martinis <f3fbe4c4218d2421400bf0bd07366865fd7a0c7e@chromium.org>

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py