V8: Switch ignition test steps to the standard suite alias

scripts/slave/recipes/v8.expected/full_tryserver_v8_v8_win_rel_ng.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\kill_processes.py"
     ],
     "name": "taskkill"
   },
   {
@@ skipping 314 matching lines @@
       "python",
       "-u",
       "RECIPE_MODULE[build::isolate]\\resources\\isolate.py",
       "[SLAVE_BUILD]\\v8\\tools\\swarming_client",
       "batcharchive",
       "--dump-json",
       "/path/to/tmp/json",
       "--isolate-server",
       "https://isolateserver.appspot.com",
       "--verbose",
-      "[SLAVE_BUILD]\\v8\\out\\Release\\bot_default.isolated.gen.json",
-      "[SLAVE_BUILD]\\v8\\out\\Release\\ignition.isolated.gen.json"
+      "[SLAVE_BUILD]\\v8\\out\\Release\\bot_default.isolated.gen.json"
     ],
     "name": "isolate tests",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{@@@",
-      "@@@STEP_LOG_LINE@json.output@  \"bot_default\": \"[dummy hash for bot_default]\", @@@",
-      "@@@STEP_LOG_LINE@json.output@  \"ignition\": \"[dummy hash for ignition]\"@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"bot_default\": \"[dummy hash for bot_default]\"@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
   {
     "cmd": [],
     "name": "trigger",
     "trigger_specs": [
       {
         "builder_name": "v8_win_rel_ng_triggered",
         "properties": {
           "category": "cq",
           "issue": 12853011,
           "master": "tryserver.v8",
           "parent_build_environment": {
             "GYP_DEFINES": "target_arch=x64 cool_flag=a=1"
           },
           "parent_got_revision": "f2cbea7e89a45f46819777bb78a1f5bd0241f64c",
           "parent_got_revision_cp": "refs/heads/master@{#50110}",
           "parent_got_swarming_client_revision": "e4fee0b18f8163be6097c9c571640038896debc4",
           "patch_project": "v8",
           "patch_storage": "rietveld",
           "patchset": "1",
           "reason": "CQ",
           "requester": "commit-bot@chromium.org",
           "revision": "12345",
           "rietveld": "https://codereview.chromium.org",
           "swarm_hashes": {
-            "bot_default": "[dummy hash for bot_default]",
-            "ignition": "[dummy hash for ignition]"
+            "bot_default": "[dummy hash for bot_default]"
           }
         }
       }
     ],
     "~followup_annotations": [
       "@@@STEP_TEXT@v8_win_rel_ng_triggered@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]