Recipes: make cwd default to slave_build

scripts/slave/recipes/v8.expected/full_tryserver_v8_v8_win64_dbg.json

Index: scripts/slave/recipes/v8.expected/full_tryserver_v8_v8_win64_dbg.json
diff --git a/scripts/slave/recipes/v8.expected/full_tryserver_v8_v8_win64_dbg.json b/scripts/slave/recipes/v8.expected/full_tryserver_v8_v8_win64_dbg.json
index 7a6c82cf81867b02b0ee100fe52b49289cfc23c4..59511ab63d5dea7ad854421120e2d24ffe0cca80 100644
--- a/scripts/slave/recipes/v8.expected/full_tryserver_v8_v8_win64_dbg.json
+++ b/scripts/slave/recipes/v8.expected/full_tryserver_v8_v8_win64_dbg.json
@@ -5,6 +5,7 @@
       "-u",
       "[BUILD]\\scripts\\slave\\kill_processes.py"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "taskkill"
   },
   {
@@ -33,6 +34,7 @@
       "--no_shallow",
       "--output_manifest"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "bot_update",
     "~followup_annotations": [
       "@@@STEP_TEXT@Some step text@@@",
@@ -65,6 +67,7 @@
       "[DEPOT_TOOLS]\\gclient.py",
       "runhooks"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "GYP_DEFINES": "dcheck_always_on=1 fastbuild=1 target_arch=x64 v8_enable_slow_dchecks=1 v8_optimized_debug=1 v8_target_arch=x64",
       "GYP_MSVS_VERSION": "2013"
@@ -77,6 +80,7 @@
       "-u",
       "[BUILD]\\scripts\\slave\\cleanup_temp.py"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "cleanup_temp"
   },
   {
@@ -94,6 +98,7 @@
       "x64",
       "--"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "compile"
   },
   {