Re-enable DepsCache using GOMA_DEPS_CACHE_FILE

scripts/slave/recipes/v8.expected/full_client_v8_V8_Linux64___builder.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--spec",
       "cache_dir = '[GIT_CACHE]'\nsolutions = [{'deps_file': '.DEPS.git', 'managed': True, 'name': 'v8', 'url': 'https://chromium.googlesource.com/v8/v8'}]",
       "--patch_root",
       "v8",
@@ skipping 268 matching lines @@
       "--src-dir",
       "[SLAVE_BUILD]/v8",
       "--goma-cache-dir",
       "[GOMA_CACHE]",
       "--buildbot-buildername",
       "V8 Linux64 - builder",
       "--buildbot-mastername",
       "client.v8",
       "--buildbot-slavename",
       "TestSlavename",
+      "--goma-deps-cache-file",
+      "V8_Linux64___builder.gomadeps",
       "--compiler",
       "goma",
       "--goma-jsonstatus",
       "/path/to/tmp/json",
       "--goma-service-account-json-file",
       "/creds/service_accounts/service-account-goma-client.json",
       "--goma-dir",
       "[CACHE]/cipd/goma",
       "--"
     ],
@@ skipping 183 matching lines @@
     "~followup_annotations": [
       "@@@STEP_TEXT@v8_trigger_proxy@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]