Revert of [Sync] Merge sync_unit_tests into components_unit_tests.

ios/build/bots/tests/common_tests.json

 {
   "tests": [
     {
       "app": "base_unittests"
     },
     {
       "app": "components_unittests"
     },
     {
       "app": "crypto_unittests"
@@ skipping 19 matching lines @@
     {
       "app": "net_unittests"
     },
     {
       "app": "skia_unittests"
     },
     {
       "app": "sql_unittests"
     },
     {
+      "app": "sync_unit_tests"
+    },
+    {
       "app": "ui_base_unittests"
     },
     {
       "app": "url_unittests"
     }
   ]
 }