Rename "service_unittests" -> "services_unittests".

testing/buildbot/chromium.linux.json

 {
   "Android Arm64 Builder (dbg)": {
     "additional_compile_targets": [
       "all"
     ]
   },
   "Android Builder": {
     "additional_compile_targets": [
       "cronet_test_instrumentation_apk",
       "system_webview_apk"
@@ skipping 2788 matching lines @@
             {
               "link": [
                 "https://luci-logdog.appspot.com/v/?s",
                 "=android%2Fswarming%2Flogcats%2F",
                 "${TASK_ID}%2F%2B%2Funified_logcats"
               ],
               "name": "shard #${SHARD_INDEX} logcats"
             }
           ]
         },
-        "test": "service_unittests"
+        "test": "services_unittests"
       },
       {
         "merge": {
           "args": [
             "--bucket",
             "chromium-result-details",
             "--test-name",
             "sql_unittests"
           ],
           "script": "//build/android/pylib/results/presentation/test_results_presentation.py"
@@ skipping 1192 matching lines @@
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
         "test": "service_manager_unittests"
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "service_unittests"
+        "test": "services_unittests"
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
         "test": "skia_unittests"
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
@@ skipping 634 matching lines @@
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
         "test": "service_manager_unittests"
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "service_unittests"
+        "test": "services_unittests"
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
         "test": "skia_unittests"
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
@@ skipping 388 matching lines @@
         ],
         "swarming": {
           "can_use_on_swarming_builders": true
         },
         "test": "sandbox_linux_unittests"
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
-        "test": "service_unittests"
+        "test": "services_unittests"
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
         "test": "skia_unittests"
       },
       {
         "swarming": {
           "can_use_on_swarming_builders": true
@@ skipping 64 matching lines @@
         "isolate_name": "telemetry_unittests",
         "name": "telemetry_unittests",
         "swarming": {
           "can_use_on_swarming_builders": true,
           "shards": 4
         }
       }
     ]
   }
 }