Recipes: make cwd default to slave_build

scripts/slave/recipes/gpu/download_and_test.expected/linux_debug.json

Index: scripts/slave/recipes/gpu/download_and_test.expected/linux_debug.json
diff --git a/scripts/slave/recipes/gpu/download_and_test.expected/linux_debug.json b/scripts/slave/recipes/gpu/download_and_test.expected/linux_debug.json
index 022ac897927da21c8b57f537757ae4d92524f460..7b9cf88b40cee97c51a0470695b894ef850c2719 100644
--- a/scripts/slave/recipes/gpu/download_and_test.expected/linux_debug.json
+++ b/scripts/slave/recipes/gpu/download_and_test.expected/linux_debug.json
@@ -5,6 +5,7 @@
       "-u",
       "[BUILD]/scripts/slave/cleanup_temp.py"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "cleanup temp"
   },
   {
@@ -17,6 +18,7 @@
       "--url",
       "https://chromium.googlesource.com/external/swarming.client.git"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "git setup (swarming_client)"
   },
   {
@@ -77,6 +79,7 @@
       "-u",
       "exit()"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "copy parent_got_revision to got_revision",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@python.inline@exit()@@@",
@@ -90,6 +93,7 @@
       "-9",
       "gnome-keyring-daemon"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "killall gnome-keyring-daemon"
   },
   {
@@ -126,6 +130,7 @@
       "--",
       "--use-gpu-in-tests"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "content_gl_tests"
   },
   {
@@ -162,6 +167,7 @@
       "--",
       "--use-gpu-in-tests"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "gl_tests"
   },
   {
@@ -198,6 +204,7 @@
       "--",
       "--use-gpu-in-tests"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "angle_unittests"
   },
   {
@@ -246,6 +253,7 @@
       "--output-dir",
       "/path/to/tmp/"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "CHROME_DEVEL_SANDBOX": "/opt/chromium/chrome_sandbox"
     },
@@ -305,6 +313,7 @@
       "--output-dir",
       "/path/to/tmp/"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "CHROME_DEVEL_SANDBOX": "/opt/chromium/chrome_sandbox"
     },
@@ -355,6 +364,7 @@
       "--output-dir",
       "/path/to/tmp/"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "CHROME_DEVEL_SANDBOX": "/opt/chromium/chrome_sandbox"
     },
@@ -405,6 +415,7 @@
       "--output-dir",
       "/path/to/tmp/"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "CHROME_DEVEL_SANDBOX": "/opt/chromium/chrome_sandbox"
     },
@@ -455,6 +466,7 @@
       "--output-dir",
       "/path/to/tmp/"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "CHROME_DEVEL_SANDBOX": "/opt/chromium/chrome_sandbox"
     },
@@ -505,6 +517,7 @@
       "--output-dir",
       "/path/to/tmp/"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "CHROME_DEVEL_SANDBOX": "/opt/chromium/chrome_sandbox"
     },
@@ -555,6 +568,7 @@
       "--output-dir",
       "/path/to/tmp/"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "CHROME_DEVEL_SANDBOX": "/opt/chromium/chrome_sandbox"
     },
@@ -605,6 +619,7 @@
       "--output-dir",
       "/path/to/tmp/"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "CHROME_DEVEL_SANDBOX": "/opt/chromium/chrome_sandbox"
     },
@@ -655,6 +670,7 @@
       "--output-dir",
       "/path/to/tmp/"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "CHROME_DEVEL_SANDBOX": "/opt/chromium/chrome_sandbox"
     },
@@ -709,6 +725,7 @@
       "--output-dir",
       "/path/to/tmp/"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "CHROME_DEVEL_SANDBOX": "/opt/chromium/chrome_sandbox"
     },