[CQ] Add node-integration bot as 10% experiment

Bug: v8:6154
NOTRY=true
TBR=yangguo@chromium.org

Change-Id: I29e8fd8e12c43478086a35a28249f5f66cd30b6b
Reviewed-on: https://chromium-review.googlesource.com/467429Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44397}

infra/config/cq.cfg

@@ -32,6 +32,10 @@ verifiers {
     buckets {
       name: "master.tryserver.v8"
       builders { name: "v8_android_arm_compile_rel" }
+      builders {
+        name: "v8_node_linux64_rel"
+        experiment_percentage: 10
+      }
       builders { name: "v8_linux64_asan_rel_ng" }
       builders {
         name: "v8_linux64_asan_rel_ng_triggered"