[Benchmarking] Re-add gpu_perftests target.

This is necessary for Pinpoint, which still uses these isolates.
This is a fix after https://chromium-review.googlesource.com/c/chromium/src/+/2003767 landed.
See the bug for details.

TBR=bsheedy@chromium.org

Bug: 1042778
Change-Id: Iff81712f2e3f6d26171064922056361e9fc7b4e7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2006391Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: Caleb Rouleau <crouleau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732746}

testing/buildbot/gn_isolate_map.pyl

@@ -851,6 +851,18 @@
     "label": "//google_apis:google_apis_unittests",
     "type": "console_test_launcher",
   },
+  "gpu_perftests": {
+    "args": [
+      "gpu_perftests",
+      "--non-telemetry=true",
+      "--adb-path",
+      "src/third_party/android_sdk/public/platform-tools/adb",
+    ],
+    "label": "//gpu:gpu_perftests",
+    "skip_usage_check": True,  # Used by Pinpoint: crbug.com/1042778
+    "script": "//testing/scripts/run_performance_tests.py",
+    "type": "script",
+  },
   "gpu_unittests": {
     "label": "//gpu:gpu_unittests",
     "type": "windowed_test_launcher",