Revert "[CQ] Temporarily drop gcc bots from CQ"

This reverts commit e234176b.

Reason for revert: goma problem fixed

Original change's description:
> [CQ] Temporarily drop gcc bots from CQ
> 
> NOTRY=true
> NOTREECHECKS=true
> TBR=yangguo@chromium.org
> 
> Bug: chromium:814810
> Change-Id: Ibf9d5d637f4e98a295d0cde6632679c77c3a4eb3
> Reviewed-on: https://chromium-review.googlesource.com/931921
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Commit-Queue: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#51478}

TBR=machenbach@chromium.org,yangguo@chromium.org

Change-Id: Ifb4af81d4ccb784ec724d6ca4ab351f1df0db755
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:814810
Reviewed-on: https://chromium-review.googlesource.com/934801Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51527}

infra/config/cq.cfg

@@ -30,10 +30,7 @@ verifiers {
         name: "v8_linux64_asan_rel_ng_triggered"
         triggered_by: "v8_linux64_asan_rel_ng"
       }
-      builders {
-        name: "v8_linux64_gcc_compile_dbg"
-        experiment_percentage: 100
-      }
+      builders { name: "v8_linux64_gcc_compile_dbg" }
       builders { name: "v8_linux64_rel_ng" }
       builders {
         name: "v8_linux64_rel_ng_triggered"
@@ -68,10 +65,7 @@ verifiers {
         name: "v8_linux_dbg_ng_triggered"
         triggered_by: "v8_linux_dbg_ng"
       }
-      builders {
-        name: "v8_linux_gcc_compile_rel"
-        experiment_percentage: 100
-      }
+      builders { name: "v8_linux_gcc_compile_rel" }
       builders { name: "v8_linux_mips64el_compile_rel" }
       builders { name: "v8_linux_mipsel_compile_rel" }
       builders { name: "v8_linux_nodcheck_rel_ng" }