[autotest] Extract filtered_files logic

BUG=chromium:672348
TEST=None

Change-Id: I9cfb007c4a7083a88219ec501e476d78a7fe7664
Reviewed-on: https://chromium-review.googlesource.com/447790
Commit-Ready: Allen Li <ayatane@chromium.org>
Tested-by: Allen Li <ayatane@chromium.org>
Reviewed-by: Prathmesh Prabhu <pprabhu@chromium.org>
diff --git a/server/cros/dynamic_suite/suite.py b/server/cros/dynamic_suite/suite.py
index 0268350..fad1f20 100644
--- a/server/cros/dynamic_suite/suite.py
+++ b/server/cros/dynamic_suite/suite.py
@@ -355,7 +355,8 @@
 
     logging.debug('Parsing control files ...')
     matcher = re.compile(r'[^/]+/(deps|profilers)/.+')
-    for file in filter(lambda f: not matcher.match(f), files):
+    filtered_files = filter(lambda f: not matcher.match(f), files)
+    for file in filtered_files:
         if _should_batch_with(cf_getter):
             text = suite_info[file]
         else: