runtime recipe_module: is_experimental should default to False.

R=iannucci@chromium.org

Bug:
Change-Id: Ib411812e8fc71b535d05e3ae65193efad6c3cbaf
Reviewed-on: https://chromium-review.googlesource.com/773624
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
diff --git a/recipe_modules/runtime/api.py b/recipe_modules/runtime/api.py
index c204010..6d23632 100644
--- a/recipe_modules/runtime/api.py
+++ b/recipe_modules/runtime/api.py
@@ -34,4 +34,4 @@
       * Uploading to an alternate google storage file name when in non-prod mode
       * Appending a 'non-production' tag to external RPCs
     """
-    return bool(self._properties.get('is_experimental', True))
+    return bool(self._properties.get('is_experimental', False))