[e2e] improve output dir handling (#21906)

Try to clear the result dir before running the e2e.py script, to avoid failures where the directory already exists, or a file cannot be overwritten due to permission issue.

release/e2e.py

@@ -2125,16 +2125,22 @@ def run_test_config(
                     f"{out_dir}")
 
         try:
-            shutil.rmtree(out_dir, ignore_errors=True)
+            shutil.rmtree(out_dir)
+        except Exception:
+            logger.exception(
+                f"Ran into error when clearing the destination dir: {out_dir}")
+
+        try:
             # Use distutils.dir_util.copy_tree() instead of shutil.cptree(),
             # which allows existing output directory.
             from distutils.dir_util import copy_tree
             copy_tree(temp_dir, out_dir)
-            logger.info(f"Dir contents: {os.listdir(out_dir)}")
-        except Exception as e:
+        except Exception:
             logger.exception(
                 "Ran into error when copying results dir to persistent "
-                f"location: {str(e)}")
+                f"location: {out_dir}")
+
+        logger.info(f"Dir contents: {os.listdir(out_dir)}")
 
     return result