It's trying to package up specific artifacts from the sdk into a tarball so we can ship that to bots and run tests. You can see how we build the paths here:
https://codesearch.chromium.org/chromium/src/build/config/chromeos/rules.gni?rcl=5bc7e0faee56286f64f9dd3f86f4e819a2557507&l=28

Strange that the old version is still in the path. I'll look.

Looks like this was an unintended regression from https://chromium-review.googlesource.com/c/chromium/src/+/1227148. It stopped writing the runtime_deps_file, so I think builds in the lkgm roll were using stale deps_file from previous builds... :O

Uploaded https://chromium-review.googlesource.com/c/chromium/src/+/1239253 for the fix.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d09dd693ee1552b0451522581a143e04bdfda575

commit d09dd693ee1552b0451522581a143e04bdfda575
Author: Ben Pastene <bpastene@chromium.org>
Date: Fri Sep 21 18:58:10 2018

Enable write_runtime_deps for cros_vm_sanity test.

Turns out it does need it. I think MB and/or isolate has a
dependency on this file being written for isolated tests.

Bug:  888000 
Change-Id: I57f86167f0bafdb1a4d081d6811bbcff3409b551
Reviewed-on: https://chromium-review.googlesource.com/1239253
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593281}
[modify] https://crrev.com/d09dd693ee1552b0451522581a143e04bdfda575/build/config/chromeos/rules.gni
[modify] https://crrev.com/d09dd693ee1552b0451522581a143e04bdfda575/chromeos/BUILD.gn

#3 theoretically fixed this.

Just launched another amd64-generic tryjob on https://chromium-review.googlesource.com/c/chromium/src/+/1237864:
https://ci.chromium.org/p/chromium/builders/luci.chromium.try/chromeos-amd64-generic-rel/93846

I'll watch how that does.

The latest roll landed: r4ed5a2ce1f076bd85d19b79ecebf1c355087921b

This should be fixed.