Revert of recipe engine: extract infra-specific paths out of the engine

recipe_modules/step/example.expected/infra_failure.json

 [
   {
     "cmd": [
       "echo",
       "Hello World"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "hello"
   },
   {
     "cmd": [
       "echo",
       "Why hello, there."
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "hello (2)"
   },
   {
     "cmd": [
       "bash",
       "-c",
       "echo Good bye, $friend."
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "friend": "Darth Vader"
     },
     "name": "goodbye"
   },
   {
     "cmd": [
       "recipes.py",
       "--help"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "PATH": "RECIPE_PACKAGE_REPO[recipe_engine]:%(PATH)s"
     },
     "name": "recipes help"
   },
   {
     "cmd": [
       "bash",
       "-c",
       "exit 3"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "anything is cool"
   },
   {
     "cmd": [
       "echo",
       "hello"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "hello (3)",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@the reason@The reason@@@",
       "@@@STEP_LOG_LINE@the reason@it failed@@@",
       "@@@STEP_LOG_END@the reason@@@",
       "@@@STEP_EXCEPTION@@@"
     ]
   },
   {
     "cmd": [],
+    "cwd": "[SLAVE_BUILD]",
     "name": "Just print stuff",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@more@More stuff@@@",
       "@@@STEP_LOG_END@more@@@"
     ]
   },
   {
     "cmd": [
       "echo",
       "goodbye"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "goodbye (2)"
   },
   {
     "cmd": [
       "echo",
       "warning"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "warning"
   },
   {
     "cmd": [
       "echo",
       "testa"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "testa"
   },
   {
     "cmd": [
       "echo",
       "testb"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "testb"
   },
   {
     "cmd": [
       "echo",
       "cleaning",
       "up",
       "build"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "cleanup",
     "~followup_annotations": [
       "step returned non-zero exit code: 1",
       "@@@STEP_EXCEPTION@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-c",
       "import sys; print sys.argv",
       "echo",
       "main",
       "application"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "application"
   },
   {
     "name": "$result",
     "recipe_result": {
       "test_me": 3
     },
     "status_code": 0
   }
 ]