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

scripts/slave/recipes/client.drmemory.recipe_autogen.expected/win_builder.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]\\resources\\bot_update.py",
       "--spec",
       "cache_dir = '[GIT_CACHE]'\nsolutions = [{'custom_deps': {'drmemory/dynamorio': 'https://github.com/DynamoRIO/dynamorio.git', 'tools/buildbot': 'https://github.com/DynamoRIO/buildbot.git'}, 'deps_file': '.DEPS.git', 'managed': True, 'name': 'drmemory', 'url': 'https://github.com/DynamoRIO/drmemory.git'}]",
       "--patch_root",
       "drmemory",
@@ skipping 90 matching lines @@
     "cwd": "[SLAVE_BUILD]",
     "env": {
       "BOTTOOLS": "[SLAVE_BUILD]\\tools\\buildbot\\bot_tools"
     },
     "name": "create sfx archive"
   },
   {
     "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]\\DrMemory-Windows-1.2.3-0x1234567-sfx.exe",
       "[SLAVE_BUILD]\\drmemory-windows-latest-sfx.exe"
     ],
     "name": "copy locally"
   },
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[build::gsutil]\\resources\\gsutil_wrapper.py",
@@ skipping 26 matching lines @@
     "~followup_annotations": [
       "@@@STEP_LINK@gsutil.upload@https://storage.cloud.google.com/chromium-drmemory-builds/builds/@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]