Move net_unittests on the internal CrOS VM bot to the main test pool.

This is similar to crrev.com/c/2490549, but for the internal VM bots.

Will move this single suite over just to test things out, then likely
more the rest over in a follow-up.

Bug: 1132206
Change-Id: I8c52aaa624d1d4b3ca5771380deb29fae69318ae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2511854Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823213}

testing/buildbot/chrome.json

@@ -471,11 +471,25 @@
           ],
           "dimension_sets": [
             {
+              "cpu": "x86",
               "kvm": "1",
               "os": "Ubuntu-16.04",
-              "pool": "chrome.tests.cros-vm"
+              "pool": "chrome.tests"
+            }
+          ],
+          "named_caches": [
+            {
+              "name": "cros_vm",
+              "path": "magic_cros_vm_cache"
             }
           ],
+          "optional_dimensions": {
+            "60": [
+              {
+                "caches": "cros_vm"
+              }
+            ]
+          },
           "service_account": "chrome-tester@chops-service-accounts.iam.gserviceaccount.com",
           "shards": 3
         },

testing/buildbot/test_suite_exceptions.pyl

@@ -1879,6 +1879,31 @@
           '--test-launcher-filter-file=../../testing/buildbot/filters/android.emulator.net_unittests.filter',
         ],
       },
+      # TODO(crbug.com/1132206): Apply this to all of the bot's tests if the
+      # cache affinity works.
+      'chromeos-betty-pi-arc-chrome': {
+        'swarming': {
+          'dimension_sets': [
+            {
+              'cpu': 'x86',
+              'pool': 'chrome.tests',
+            }
+          ],
+          'optional_dimensions': {
+            '60': [
+              {
+                'caches': 'cros_vm',
+              }
+            ],
+          },
+          'named_caches': [
+            {
+              'name': 'cros_vm',
+              'path': 'magic_cros_vm_cache',
+            },
+          ],
+        },
+      },
       'linux-blink-heap-concurrent-marking-tsan-rel': {
         'swarming': {
           'shards': 4,