Revert "[CQ] Temporarily make avx2 trybot experimental."

This reverts commit 2ec46bec.

Reason for revert:
avx2 builders have moved to the chromium swarming pool

Original change's description:
> [CQ] Temporarily make avx2 trybot experimental.
> 
> NOTRY=true
> NOPRESUBMIT=true
> TBR=tandrii@chromium.org
> 
> Bug: chromium:736757
> Change-Id: I920eda5c916981d3588fb7346ec4e811dc5112aa
> Reviewed-on: https://chromium-review.googlesource.com/548360
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Commit-Queue: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#46219}

TBR=machenbach@chromium.org,tandrii@chromium.org,clemensh@chromium.org

Change-Id: If228a34be2e6e88dbd2cc3fc1de0b227c4d113c2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:736757
Reviewed-on: https://chromium-review.googlesource.com/549321Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46236}

infra/config/cq.cfg

@@ -38,15 +38,11 @@ verifiers {
         name: "v8_linux64_asan_rel_ng_triggered"
         triggered_by: "v8_linux64_asan_rel_ng"
       }
-      # TODO(machenbach): Reenable when http://crbug.com/736757 is resolved.
+      builders { name: "v8_linux64_avx2_rel_ng" }
       builders {
-        name: "v8_linux64_avx2_rel_ng"
-        experiment_percentage: 100
+        name: "v8_linux64_avx2_rel_ng_triggered"
+        triggered_by: "v8_linux64_avx2_rel_ng"
       }
-      # builders {
-      #   name: "v8_linux64_avx2_rel_ng_triggered"
-      #   triggered_by: "v8_linux64_avx2_rel_ng"
-      # }
       builders { name: "v8_linux64_gcc_compile_dbg" }
       builders { name: "v8_linux64_gyp_rel_ng" }
       builders {