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

recipe_modules/step/example.expected/exceptional.json

Index: recipe_modules/step/example.expected/exceptional.json
diff --git a/recipe_modules/step/example.expected/exceptional.json b/recipe_modules/step/example.expected/exceptional.json
index 01c8e351823c9a049653ed39d4a1c8be11af1cdc..7dfb37591357b8dfe6d869d57f002bf841c79d90 100644
--- a/recipe_modules/step/example.expected/exceptional.json
+++ b/recipe_modules/step/example.expected/exceptional.json
@@ -4,6 +4,7 @@
       "echo",
       "Hello World"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "hello"
   },
   {
@@ -11,6 +12,7 @@
       "echo",
       "Why hello, there."
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "hello (2)"
   },
   {
@@ -19,6 +21,7 @@
       "-c",
       "echo Good bye, $friend."
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "friend": "Darth Vader"
     },
@@ -29,6 +32,7 @@
       "recipes.py",
       "--help"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "env": {
       "PATH": "RECIPE_PACKAGE_REPO[recipe_engine]:%(PATH)s"
     },
@@ -40,6 +44,7 @@
       "-c",
       "exit 3"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "anything is cool"
   },
   {
@@ -47,6 +52,7 @@
       "echo",
       "hello"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "hello (3)",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@the reason@The reason@@@",
@@ -57,6 +63,7 @@
   },
   {
     "cmd": [],
+    "cwd": "[SLAVE_BUILD]",
     "name": "Just print stuff",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@more@More stuff@@@",
@@ -68,6 +75,7 @@
       "echo",
       "goodbye"
     ],
+    "cwd": "[SLAVE_BUILD]",
     "name": "goodbye (2)",
     "~followup_annotations": [
       "step returned non-zero exit code: 1",