V8: Move gn-peek step behind mb step

scripts/slave/recipes/v8.expected/full_client_v8_V8_Linux64___gcov_coverage.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--master",
       "client.v8",
       "--builder",
       "V8 Linux64 - gcov coverage",
@@ skipping 131 matching lines @@
       "GYP_DEFINES": "clang=0 coverage=1 gomadir='[CACHE]/cipd/goma' target_arch=x64 use_goma=1 v8_target_arch=x64",
       "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": [
+      "lcov",
+      "--directory",
+      "[SLAVE_BUILD]/v8/out/Release",
+      "--zerocounters"
+    ],
+    "name": "lcov zero counters"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
       "[DEPOT_TOOLS]/gn.py",
       "--root=[SLAVE_BUILD]/v8",
       "gen",
       "[TMP_BASE]/v8_gn_tmp_1",
       "--args=is_debug=false target_cpu=\"x64\" use_goma=true goma_dir=\"[CACHE]/cipd/goma\""
     ],
     "name": "gn"
   },
   {
     "cmd": [
@@ skipping 22 matching lines @@
       "@@@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"
-  },
-  {
-    "cmd": [
-      "lcov",
-      "--directory",
-      "[SLAVE_BUILD]/v8/out/Release",
-      "--zerocounters"
-    ],
-    "name": "lcov zero counters"
-  },
-  {
-    "cmd": [
-      "python",
-      "-u",
-      "RECIPE_PACKAGE_REPO[build]/scripts/tools/runit.py",
-      "--show-path",
-      "python",
       "RECIPE_PACKAGE_REPO[build]/scripts/slave/compile.py",
       "--gsutil-py-path",
       "RECIPE_PACKAGE_REPO[depot_tools]/gsutil.py",
       "--ninja-path",
       "RECIPE_PACKAGE_REPO[depot_tools]/ninja",
       "--target",
       "Release",
       "--src-dir",
       "[SLAVE_BUILD]/v8",
       "--goma-cache-dir",
@@ skipping 116 matching lines @@
     "~followup_annotations": [
       "@@@STEP_LINK@report@https://storage.googleapis.com/chromium-v8/linux64_gcov_rel/f2cbea7e89a45f46819777bb78a1f5bd0241f64c/index.html@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]