[Telemetry] Disable core-scroll-header-panel which was recently enabled.

It did pass two runs, but is consistently failing now. So I'm not sure
whether this is a regression or flake. Since the test is so new, it seems
safest to just disable this page until it shakes out.

If this isn't a flake, the regression range is r283974-284019.

BUG=394756
TBR=wiltzius@chromium.org
NOTRY=True

Review URL: https://codereview.chromium.org/400823006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284114 0039d316-1c4b-4281-b951-d872f2087c98

tools/perf/page_sets/polymer.py

@@ -216,6 +216,9 @@ class PolymerPageSet(page_set_module.PageSet):
       self.AddPage(PolymerSampler(self, p))
 
     # Polymer Sampler subpages that are interesting to scroll
-    SCROLLABLE_PAGES = ['core-scroll-header-panel']
+    SCROLLABLE_PAGES = [
+        # crbug.com/394756
+        # 'core-scroll-header-panel',
+        ]
     for p in SCROLLABLE_PAGES:
       self.AddPage(PolymerSampler(self, p, scrolling_page=True))