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

scripts/slave/recipe_modules/chromium_android/example.expected/tester_offline_devices.json

Index: scripts/slave/recipe_modules/chromium_android/example.expected/tester_offline_devices.json
diff --git a/scripts/slave/recipe_modules/chromium_android/example.expected/tester_offline_devices.json b/scripts/slave/recipe_modules/chromium_android/example.expected/tester_offline_devices.json
index 75082ed52bd9124c76f8d41c2e3c7f9a05d48b4d..565be7c9eb950f03a0b1e1d702266aa6aac501b5 100644
--- a/scripts/slave/recipe_modules/chromium_android/example.expected/tester_offline_devices.json
+++ b/scripts/slave/recipe_modules/chromium_android/example.expected/tester_offline_devices.json
@@ -188,7 +188,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
+      "\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",
       "[SLAVE_BUILD]/src/chrome/VERSION",
       "/path/to/tmp/"
     ],
@@ -564,7 +564,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
+      "\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",
       "[HOME]/.android/known_devices.json",
       "/path/to/tmp/"
     ],
@@ -853,7 +853,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport shutil\nimport sys\nshutil.copy(sys.argv[1], sys.argv[2])\n",
+      "\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",
       "[SLAVE_BUILD]/src/chrome/VERSION",
       "/path/to/tmp/"
     ],