Swarm setup_unittests on Win bots that run installer_util_unittests.

testing/buildbot/chromium.win.json

Index: testing/buildbot/chromium.win.json
diff --git a/testing/buildbot/chromium.win.json b/testing/buildbot/chromium.win.json
index 4bbee12577efeae40fea81887d7523155533b1ed..1a941f3d4d3c096477ef95046fd6f6e39ba7c729 100644
--- a/testing/buildbot/chromium.win.json
+++ b/testing/buildbot/chromium.win.json
@@ -241,6 +241,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "setup_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "skia_unittests"
       },
       {
@@ -572,6 +578,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "setup_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "skia_unittests"
       },
       {
@@ -1026,6 +1038,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "setup_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "skia_unittests"
       },
       {
@@ -1337,6 +1355,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "setup_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "skia_unittests"
       },
       {
@@ -1807,6 +1831,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "setup_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "skia_unittests"
       },
       {