[perf] Reduce number of articles to visit on browse:news:nytimes:2019

Bug: chromium:1050534
Change-Id: I6c434317ffb670adca63f542563e7c7aa979faa3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2050319Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#740361}

tools/perf/page_sets/system_health/browsing_stories.py

@@ -227,6 +227,8 @@ class NytimesMobileStory2019(_ArticleBrowsingStory):
   NAME = 'browse:news:nytimes:2019'
   URL = 'http://mobile.nytimes.com'
   ITEM_SELECTOR = '.css-1yjtett a'
+  # Nytimes is very heavy so only visit 2 articles.
+  ITEMS_TO_VISIT = 2
   SUPPORTED_PLATFORMS = platforms.MOBILE_ONLY
   TAGS = [story_tags.YEAR_2019]