Move benchmark tests to their own CI script (#6779)

.github/workflows/build.yaml

diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index dc6a72a..ef812be 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -111,7 +111,6 @@
           - build_dart2js
           - test_ddc
           - test_dart2js
-          - benchmarks_dart2js
     steps:
       - name: git clone
         uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
@@ -257,6 +256,25 @@
           DEVTOOLS_PACKAGE: devtools_extensions
         run: ./tool/ci/bots.sh
 
+  benchmarks:
+    name: benchmarks
+    needs: flutter-prep
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - name: git clone
+        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+      - name: Load Cached Flutter SDK
+        uses: actions/cache@704facf57e6136b1bc63b828d79edcd491f0ee84
+        with:
+          path: |
+            ./flutter-sdk
+          key: flutter-sdk-${{ runner.os }}-${{ needs.flutter-prep.outputs.latest_flutter_candidate }}
+      - name: tool/ci/benchmark_tests.sh
+        run: ./tool/ci/benchmark_tests.sh
+
+
 # TODO(https://github.com/flutter/devtools/issues/1715): add a windows compatible version of tool/ci/bots.sh
 # and run it from this job.
 #  windows-test:

packages/devtools_app/test_benchmarks/README.md

diff --git a/packages/devtools_app/test_benchmarks/README.md b/packages/devtools_app/test_benchmarks/README.md
index 48c9cbf..641b760 100644
--- a/packages/devtools_app/test_benchmarks/README.md
+++ b/packages/devtools_app/test_benchmarks/README.md
@@ -9,4 +9,4 @@
 
 ## Running a benchmark test on the CI
 
-The benchmark tests are run automatically on the CI. See the "benchmarks_dart2js" job.
+The benchmark tests are run automatically on the CI. See the "benchmarks" job.

tool/ci/benchmark_tests.sh

diff --git a/tool/ci/benchmark_tests.sh b/tool/ci/benchmark_tests.sh
new file mode 100755
index 0000000..e0083e9
--- /dev/null
+++ b/tool/ci/benchmark_tests.sh
@@ -0,0 +1,14 @@
+#!/bin/bash
+
+# Copyright 2018 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Fast fail the script on failures.
+set -ex
+
+source ./tool/ci/setup.sh
+
+pushd $DEVTOOLS_DIR/packages/devtools_app
+dart run test_benchmarks/web_bundle_size_test.dart
+popd

tool/ci/bots.sh

diff --git a/tool/ci/bots.sh b/tool/ci/bots.sh
index eb7ff61..98fc27b 100755
--- a/tool/ci/bots.sh
+++ b/tool/ci/bots.sh
@@ -93,11 +93,6 @@
         dart run integration_test/run_tests.dart --headless
         popd
     fi
-
-elif [ "$BOT" = "benchmarks_dart2js" ]; then
-
-    dart run test_benchmarks/web_bundle_size_test.dart
-
 fi
 
 popd