Make skia recipes explicitly set GIT_MODE

scripts/slave/recipes/skia/swarm_trigger.expected/recipe_in_skia_repo.json

 [
   {
     "cmd": [
       "git",
       "remote",
       "set-url",
       "origin",
       "https://skia.googlesource.com/skia.git"
     ],
     "cwd": "[SLAVE_BUILD]/skia",
@@ skipping 27 matching lines @@
     "cwd": "[SLAVE_BUILD]/skia",
     "name": "git clean"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[depot_tools]/gclient.py",
       "config",
       "--spec",
-      "cache_dir = None\nsolutions = [{'deps_file': 'DEPS', 'managed': False, 'name': 'skia', 'url': 'https://skia.googlesource.com/skia.git'}]\ntarget_os = ['llvm']"
+      "cache_dir = None\nsolutions = [{'deps_file': '.DEPS.git', 'managed': False, 'name': 'skia', 'url': 'https://skia.googlesource.com/skia.git'}]\ntarget_os = ['llvm']"
     ],
     "env": {
       "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
     },
     "name": "gclient setup"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[depot_tools]/gclient.py",
       "sync",
+      "--verbose",
+      "--with_branch_heads",
       "--nohooks",
+      "-j8",
+      "--reset",
       "--force",
-      "--verbose",
+      "--upstream",
+      "--no-nag-max",
       "--delete_unversioned_trees",
       "--revision",
       "skia@abc123",
       "--output-json",
       "/path/to/tmp/json"
     ],
     "env": {
       "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
     },
     "name": "gclient sync",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"solutions\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"skia/\": {@@@",
-      "@@@STEP_LOG_LINE@json.output@      \"revision\": 164710@@@",
+      "@@@STEP_LOG_LINE@json.output@      \"revision\": \"9046e2e693bb92a76e972b694580e5d17ad10748\"@@@",
       "@@@STEP_LOG_LINE@json.output@    }@@@",
       "@@@STEP_LOG_LINE@json.output@  }@@@",
       "@@@STEP_LOG_LINE@json.output@}@@@",
       "@@@STEP_LOG_END@json.output@@@",
-      "@@@SET_BUILD_PROPERTY@got_revision@164710@@@"
+      "@@@SET_BUILD_PROPERTY@got_revision@\"9046e2e693bb92a76e972b694580e5d17ad10748\"@@@"
     ]
   },
   {
+    "cmd": [
+      "python",
+      "-u",
+      "RECIPE_PACKAGE_REPO[depot_tools]/gclient.py",
+      "recurse",
+      "git",
+      "config",
+      "user.name",
+      "local_bot"
+    ],
+    "env": {
+      "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
+    },
+    "name": "gclient recurse (git config user.name)"
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "RECIPE_PACKAGE_REPO[depot_tools]/gclient.py",
+      "recurse",
+      "git",
+      "config",
+      "user.email",
+      "local_bot@example.com"
+    ],
+    "env": {
+      "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]"
+    },
+    "name": "gclient recurse (git config user.email)"
+  },
+  {
     "allow_subannotations": true,
     "cmd": [
       "python",
       "[SLAVE_BUILD]/skia/infra/bots/recipes.py",
       "run",
       "--workdir",
       "[SLAVE_BUILD]",
       "swarm_trigger",
       "path_config=kitchen",
       "buildername=Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Debug",
       "recipe=skia/swarm_trigger",
       "mastername=client.skia",
       "buildnumber=5",
       "slavename=skiabot-linux-compile-000",
       "path_config=kitchen",
       "revision=abc123"
     ],
     "name": "run recipe"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]