Recipes: make cwd default to slave_build

scripts/slave/recipes/v8.expected/full_client_v8_V8_Win32___debug___1.json

Index: scripts/slave/recipes/v8.expected/full_client_v8_V8_Win32___debug___1.json
diff --git a/scripts/slave/recipes/v8.expected/full_client_v8_V8_Win32___debug___1.json b/scripts/slave/recipes/v8.expected/full_client_v8_V8_Win32___debug___1.json
index bc7b233369c449d350c4ba01b08e23528f5def3f..f7b1defb02f3014df4c2d54b7bf20edac7a04000 100644
--- a/scripts/slave/recipes/v8.expected/full_client_v8_V8_Win32___debug___1.json
+++ b/scripts/slave/recipes/v8.expected/full_client_v8_V8_Win32___debug___1.json
@@ -5,6 +5,7 @@
       "-u",
       "[BUILD]\\scripts\\slave\\kill_processes.py"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "taskkill"
   },
   {
@@ -31,6 +32,7 @@
       "--no_shallow",
       "--output_manifest"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "bot_update",
     "~followup_annotations": [
       "@@@STEP_TEXT@Some step text@@@",
@@ -63,6 +65,7 @@
       "[DEPOT_TOOLS]\\gclient.py",
       "runhooks"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "GYP_DEFINES": "target_arch=ia32 v8_enable_slow_dchecks=1 v8_optimized_debug=1 v8_target_arch=ia32"
     },
@@ -74,6 +77,7 @@
       "-u",
       "[BUILD]\\scripts\\slave\\cleanup_temp.py"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "cleanup_temp"
   },
   {
@@ -83,6 +87,7 @@
       "\nimport os, sys\nfrom common import chromium_utils\n\nif os.path.exists(sys.argv[1]):\n  chromium_utils.RemoveDirectory(sys.argv[1])\n",
       "[SLAVE_BUILD]\\v8\\build\\Debug"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "rmtree build directory",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@python.inline@@@@",
@@ -110,6 +115,7 @@
       "--build-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"branch\": \"master\", \"buildername\": \"V8 Win32 - debug - 1\", \"buildnumber\": 571, \"mastername\": \"client.v8\", \"parent_buildername\": \"V8 Win32 - debug builder\", \"parent_got_revision\": \"54321\", \"recipe\": \"v8\", \"revision\": \"20123\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "extract build"
   },
   {