Revert "Fix file.copy recipe_module to not fail if files are already equal."

scripts/slave/recipe_modules/cronet/example.expected/local_test.json

Index: scripts/slave/recipe_modules/cronet/example.expected/local_test.json
diff --git a/scripts/slave/recipe_modules/cronet/example.expected/local_test.json b/scripts/slave/recipe_modules/cronet/example.expected/local_test.json
index 07620ac59471b2a695748a74d12d616c450287da..0d93143bafea0a2ffb4bf665fefb0e62300c2ebe 100644
--- a/scripts/slave/recipe_modules/cronet/example.expected/local_test.json
+++ b/scripts/slave/recipe_modules/cronet/example.expected/local_test.json
@@ -228,7 +228,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport shutil\nimport sys\n# Apparently, shutil.copy fails if files are binary-equal on *nix OSes.\n# See http://crbug.com/636168#c8.\nif hasattr(shutil, '_samefile'):\n  if shutil._samefile(sys.argv[1], sys.argv[2]):\n    sys.exit(0)\nshutil.copy(sys.argv[1], sys.argv[2])\n",
+      "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
       "[SLAVE_BUILD]/src/chrome/VERSION",
       "/path/to/tmp/"
     ],
@@ -611,7 +611,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport shutil\nimport sys\n# Apparently, shutil.copy fails if files are binary-equal on *nix OSes.\n# See http://crbug.com/636168#c8.\nif hasattr(shutil, '_samefile'):\n  if shutil._samefile(sys.argv[1], sys.argv[2]):\n    sys.exit(0)\nshutil.copy(sys.argv[1], sys.argv[2])\n",
+      "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
       "[SLAVE_BUILD]/src/chrome/VERSION",
       "/path/to/tmp/"
     ],