[sheriff] Add a bug number for a disabled test

TBR=rainhard@chromium.org
NOTRY=true

Bug: 1070886
Change-Id: I4bf958456b1602620f479802e0838d2f9dbea380
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2636875Reviewed-by: Xida Chen <xidachen@chromium.org>
Reviewed-by: Rainhard Findling <rainhard@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844777}

chrome/browser/download/save_page_browsertest.cc

@@ -1308,6 +1308,7 @@ IN_PROC_BROWSER_TEST_P(SavePageOriginalVsSavedComparisonTest, CrossSite) {
 
 // Test compares original-vs-saved for a page with <object> elements.
 // (see crbug.com/553478).
+// crbug.com/1070886: disabled because of flakiness.
 IN_PROC_BROWSER_TEST_P(SavePageOriginalVsSavedComparisonTest,
                        DISABLED_ObjectElementsViaHttp) {
   GURL url(