Re-enable CQ build cancellation for linux-chromeos-rel tryjobs.

It was disabled for linux-chromeos-rel since it supposedly caused a
regression in cycle time. However, linux-chromeos-rel is suspected to
behave similar to linux-rel in that regard, and linux-rel did not show
similar regressions.

So this tentatively re-enables cancellation on linux-chromeos-rel to
confirm if it does more harm than good.

Change-Id: I30b1f7d7514bb0b6d8ca7b2ede5cd4a494c770f0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2463854Reviewed-by: Garrett Beaty <gbeaty@chromium.org>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#816355}

infra/config/generated/commit-queue.cfg

@@ -1001,7 +1001,6 @@ config_groups {
       }
       builders {
         name: "chromium/try/linux-chromeos-rel"
-        cancel_stale: NO
         location_regexp: ".*"
         location_regexp_exclude: ".+/[+]/docs/.+"
         location_regexp_exclude: ".+/[+]/infra/config/.+"

infra/config/subprojects/chromium/try.star

@@ -600,7 +600,7 @@ try_.chromium_chromiumos_builder(
     branch_selector = branches.ALL_BRANCHES,
     goma_jobs = goma.jobs.J150,
     main_list_view = settings.main_list_view_name,
-    tryjob = try_.job(cancel_stale = False),
+    tryjob = try_.job(),
     use_clang_coverage = True,
 )