autotest: Silence stack traces from non-errors in parse

BUG=chromium:873220
TEST=None

Change-Id: I9a7868309d9d3ec3fb7a3924f5d89cafb1131c6e
Reviewed-on: https://chromium-review.googlesource.com/1171543
Commit-Ready: Prathmesh Prabhu <pprabhu@chromium.org>
Tested-by: Prathmesh Prabhu <pprabhu@chromium.org>
Reviewed-by: Xixuan Wu <xixuan@chromium.org>
diff --git a/tko/parse.py b/tko/parse.py
index 6f7c093..591221f 100755
--- a/tko/parse.py
+++ b/tko/parse.py
@@ -284,6 +284,9 @@
     )
     for control_file in hardcoded_control_file_names:
         control = os.path.join(path, control_file)
+        if not os.path.exists(control):
+            continue
+
         try:
             max_result_size_KB = control_data.parse_control(
                     control, raise_warnings=False).max_result_size_KB