V8: Move gn-peek step behind mb step

scripts/slave/recipes/v8.expected/full_client_dart_fyi_v8_linux_release.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--master",
       "client.dart.fyi",
       "--builder",
       "v8-linux-release",
@@ skipping 113 matching lines @@
       "GYP_DEFINES": "clang=1 gomadir='[CACHE]/cipd/goma' target_arch=ia32 use_goma=1 v8_enable_disassembler=1 v8_target_arch=ia32",
       "GYP_GENERATORS": "ninja",
       "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
     },
     "name": "gclient runhooks"
   },
   {
     "cmd": [
       "python",
       "-u",
+      "RECIPE_PACKAGE_REPO[build]/scripts/tools/runit.py",
+      "--show-path",
+      "python",
+      "RECIPE_PACKAGE_REPO[build]/scripts/slave/cleanup_temp.py"
+    ],
+    "name": "cleanup_temp"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
       "[DEPOT_TOOLS]/gn.py",
       "--root=[SLAVE_BUILD]/v8",
       "gen",
       "[TMP_BASE]/v8_gn_tmp_1",
       "--args=is_debug=false target_cpu=\"x86\" use_goma=true goma_dir=\"[CACHE]/cipd/goma\""
     ],
     "name": "gn"
   },
   {
     "cmd": [
@@ skipping 16 matching lines @@
     ],
     "name": "rmtree [TMP_BASE]/v8_gn_tmp_1",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@python.inline@@@@",
       "@@@STEP_LOG_LINE@python.inline@import shutil, sys@@@",
       "@@@STEP_LOG_LINE@python.inline@shutil.rmtree(sys.argv[1])@@@",
       "@@@STEP_LOG_END@python.inline@@@"
     ]
   },
   {
-    "cmd": [
-      "python",
-      "-u",
-      "RECIPE_PACKAGE_REPO[build]/scripts/tools/runit.py",
-      "--show-path",
-      "python",
-      "RECIPE_PACKAGE_REPO[build]/scripts/slave/cleanup_temp.py"
-    ],
-    "name": "cleanup_temp"
-  },
-  {
     "allow_subannotations": true,
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]/scripts/slave/clang_revision.py",
       "--src-dir",
       "[SLAVE_BUILD]/v8",
       "--output-json",
       "/path/to/tmp/json"
     ],
@@ skipping 68 matching lines @@
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"branch\": \"4.2\", \"buildername\": \"v8-linux-release\", \"buildnumber\": 571, \"mastername\": \"client.dart.fyi\", \"parent_buildername\": null, \"recipe\": \"v8\", \"revision\": \"20123\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}"
     ],
     "name": "package build"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]