Recipes: make cwd default to slave_build

scripts/slave/recipes/ios/try.expected/parent.json

Index: scripts/slave/recipes/ios/try.expected/parent.json
diff --git a/scripts/slave/recipes/ios/try.expected/parent.json b/scripts/slave/recipes/ios/try.expected/parent.json
index 5812eb3508fe555119696edfbd7bd9923c711654..f9b53d99cc7c1aa6e71cfc93d37a3b6ef5e90e4f 100644
--- a/scripts/slave/recipes/ios/try.expected/parent.json
+++ b/scripts/slave/recipes/ios/try.expected/parent.json
@@ -5,6 +5,7 @@
       "--json-file",
       "/path/to/tmp/json"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "host and tools info",
     "~followup_annotations": [
       "@@@STEP_TEXT@<br />OS X 1.2.3, Xcode 6.7.8 (5D342509a)@@@",
@@ -48,6 +49,7 @@
       "src@HEAD",
       "--force"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "bot_update",
     "~followup_annotations": [
       "@@@STEP_TEXT@Some step text@@@",
@@ -95,6 +97,7 @@
       "[SLAVE_BUILD]/src/ios/build/bots/tryserver.fake/ios.json",
       "/path/to/tmp/json"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "read build config",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{@@@",
@@ -118,6 +121,7 @@
       "[SLAVE_BUILD]/src/ios/build/bots/tryserver.fake/parent.json",
       "/path/to/tmp/json"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "read parent build config (parent)",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{@@@",
@@ -139,6 +143,7 @@
       "-e",
       "{\n  \"GYP_DEFINES\": {\n    \"OS\": \"ios\", \n    \"component\": \"static_library\", \n    \"fake gyp define 1\": \"fake value 1\", \n    \"fake gyp define 2\": \"fake value 2\"\n  }, \n  \"compiler\": \"xcodebuild\", \n  \"configuration\": \"Debug\", \n  \"sdk\": \"iphonesimulator8.0\", \n  \"tests\": [\n    {\n      \"app\": \"fake tests\", \n      \"device type\": \"fake device\", \n      \"os\": \"8.1\"\n    }\n  ], \n  \"triggered bots\": {}, \n  \"triggered by\": \"parent\", \n  \"xcode version\": \"fake xcode version\"\n}"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "finalize build config"
   },
   {
@@ -149,6 +154,7 @@
       "--version",
       "fake xcode version"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "find xcode",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{}@@@",
@@ -162,6 +168,7 @@
       "[DEPOT_TOOLS]/gclient.py",
       "runhooks"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "GYP_DEFINES": "fake gyp define 1=fake value 1 fake gyp define 2=fake value 2 component=static_library OS=ios",
       "GYP_GENERATORS": "xcode",
@@ -200,6 +207,7 @@
       "--version",
       "8.1"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "fake tests (fake device iOS 8.1)",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{@@@",