[Sheriff] Mark some same-insecure.http.html tests flaky

Expects timeout on Win 7 for
  external/wpt/referrer-policy/strict-origin-when-cross-origin/
    attr-referrer/same-origin/http-http/img-tag/keep-origin-redirect/
    same-insecure.http.html
  virtual/blink-cors/external/wpt/referrer-policy/
    strict-origin-when-cross-origin/attr-referrer/same-origin/http-http/
    img-tag/keep-origin-redirect/same-insecure.http.html
  virtual/not-omt-sw-fetch/external/wpt/referrer-policy/
    strict-origin-when-cross-origin/attr-referrer/same-origin/http-http/
    img-tag/keep-origin-redirect/same-insecure.http.html

TBR=estark@chromium.org

BUG=chromium:988890
TEST=None

Change-Id: I1f11fa9168933bcf00ce519393631f5009920fbc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1725633Reviewed-by: Lutz Justen <ljusten@chromium.org>
Commit-Queue: Lutz Justen <ljusten@chromium.org>
Cr-Commit-Position: refs/heads/master@{#682207}

third_party/blink/web_tests/TestExpectations

@@ -6416,3 +6416,6 @@ crbug.com/988074 [ Linux ] virtual/cors-rfc1918/http/tests/security/cors-rfc1918
 crbug.com/987115 [ Win Linux ] virtual/threaded/fast/scrolling/scrollbars/scrollbar-button-gesture-target.html [ Crash Pass Failure ]
 crbug.com/626703 [ Mac ] external/wpt/css/cssom-view/scrollIntoView-sideways-lr-writing-mode-and-rtl-direction.html [ Failure ]
 crbug.com/626703 [ Mac ] external/wpt/css/cssom-view/scrollIntoView-sideways-rl-writing-mode-and-rtl-direction.html [ Failure ]
+crbug.com/988890 [ Win7 Release ] external/wpt/referrer-policy/strict-origin-when-cross-origin/attr-referrer/same-origin/http-http/img-tag/keep-origin-redirect/same-insecure.http.html [ Pass Timeout ]
+crbug.com/988890 [ Win7 Release ] virtual/blink-cors/external/wpt/referrer-policy/strict-origin-when-cross-origin/attr-referrer/same-origin/http-http/img-tag/keep-origin-redirect/same-insecure.http.html [ Pass Timeout ]
+crbug.com/988890 [ Win7 Release ] virtual/not-omt-sw-fetch/external/wpt/referrer-policy/strict-origin-when-cross-origin/attr-referrer/same-origin/http-http/img-tag/keep-origin-redirect/same-insecure.http.html [ Pass Timeout ]