Convert nacl_loader_unittests to run exclusively on Swarming

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 b0b81434346c28dd508a2b84245229df73a15641..50cb0c386be0350e4324cb1c308fc4133b67f743 100644
--- a/testing/buildbot/chromium.win.json
+++ b/testing/buildbot/chromium.win.json
@@ -184,6 +184,9 @@
         "test": "mojo_system_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "nacl_loader_unittests"
       },
       {
@@ -494,6 +497,9 @@
         "test": "mojo_system_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "nacl_loader_unittests"
       },
       {
@@ -923,6 +929,9 @@
         "test": "mojo_system_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "nacl_loader_unittests"
       },
       {
@@ -1209,6 +1218,9 @@
         "test": "mojo_system_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "nacl_loader_unittests"
       },
       {
@@ -1654,6 +1666,9 @@
         "test": "midi_unittests"
       },
       {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "nacl_loader_unittests"
       },
       {