Convert net_unittests to run exclusively on Swarming

testing/buildbot/chromium.fyi.json

Index: testing/buildbot/chromium.fyi.json
diff --git a/testing/buildbot/chromium.fyi.json b/testing/buildbot/chromium.fyi.json
index 08ee1679dff751a1314e475847c6797e7d42a019..332a2f26b8b06df56d4c937ef3417a24937d15a8 100644
--- a/testing/buildbot/chromium.fyi.json
+++ b/testing/buildbot/chromium.fyi.json
@@ -1693,6 +1693,9 @@
         "test": "midi_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "net_unittests"
       },
       {
@@ -1820,6 +1823,9 @@
         "test": "midi_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "net_unittests"
       },
       {
@@ -2918,6 +2924,9 @@
         "test": "nacl_loader_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "net_unittests"
       },
       {
@@ -3302,6 +3311,9 @@
         "test": "nacl_loader_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "net_unittests"
       },
       {