Remove linux_chromium_headless_rel from the CQ

Bot is being deleted, but was deleted from some repos too quickly.

TBR=jbudorick
NOTRY=true

Bug: 893662
Change-Id: I479a6a55b45a23fec796c4bdc14805bbce1bce56
Reviewed-on: https://chromium-review.googlesource.com/c/1459980Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Stephen Martinis <martiniss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#630078}

docs/infra/cq_builders.md

@@ -60,8 +60,6 @@ These builders must pass before a CL may land.
 
 * [linux_chromium_compile_dbg_ng](https://ci.chromium.org/p/chromium/builders/luci.chromium.try/linux_chromium_compile_dbg_ng) ([`commit-queue.cfg` entry](https://cs.chromium.org/search/?q=package:%5Echromium$+file:commit-queue.cfg+chromium/try/linux_chromium_compile_dbg_ng)) ([matching builders](https://cs.chromium.org/search/?q=file:trybots.py+linux_chromium_compile_dbg_ng))
 
-* [linux_chromium_headless_rel](https://ci.chromium.org/p/chromium/builders/luci.chromium.try/linux_chromium_headless_rel) ([`commit-queue.cfg` entry](https://cs.chromium.org/search/?q=package:%5Echromium$+file:commit-queue.cfg+chromium/try/linux_chromium_headless_rel)) ([matching builders](https://cs.chromium.org/search/?q=file:trybots.py+linux_chromium_headless_rel))
-
 * [linux_chromium_tsan_rel_ng](https://ci.chromium.org/p/chromium/builders/luci.chromium.try/linux_chromium_tsan_rel_ng) ([`commit-queue.cfg` entry](https://cs.chromium.org/search/?q=package:%5Echromium$+file:commit-queue.cfg+chromium/try/linux_chromium_tsan_rel_ng)) ([matching builders](https://cs.chromium.org/search/?q=file:trybots.py+linux_chromium_tsan_rel_ng))
 
 * [mac-rel](https://ci.chromium.org/p/chromium/builders/luci.chromium.try/mac-rel) ([`commit-queue.cfg` entry](https://cs.chromium.org/search/?q=package:%5Echromium$+file:commit-queue.cfg+chromium/try/mac-rel)) ([matching builders](https://cs.chromium.org/search/?q=file:trybots.py+mac-rel))

infra/config/global/commit-queue.cfg

@@ -124,9 +124,6 @@ config_groups {
       builders {
         name: "chromium/try/linux_chromium_compile_dbg_ng"
       }
-      builders {
-        name: "chromium/try/linux_chromium_headless_rel"
-      }
       builders {
         name: "chromium/try/linux_chromium_tsan_rel_ng"
       }