Update block-size-...-content-table-1b.html TestExpectation

Turns out this test is failing on other debug builds as well, e.g.:
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Linux%20Tests%20(dbg)(1)/76911

it also has failed on a Mac 10.12 rel bot, so updating to include all Mac bots

Bug: 918905
Change-Id: I30628e6ee16674d8b961cbbbd273255f4429ad5e
Reviewed-on: https://chromium-review.googlesource.com/c/1394927
Commit-Queue: Tommy Steimel <steimel@chromium.org>
Reviewed-by: Becca Hughes <beccahughes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619803}

third_party/blink/web_tests/TestExpectations

@@ -6037,4 +6037,4 @@ crbug.com/917284 virtual/outofblink-cors/external/wpt/service-workers/service-wo
 crbug.com/917970 [ Mac10.13 Retina ] virtual/mouseevent_fractional/fast/events/popup-blocking-timers5.html [ Pass Failure ]
 
 # Sheriff 2019-01-03
-crbug.com/918905 [ Mac10.13 ] external/wpt/css/vendor-imports/mozilla/mozilla-central-reftests/sizing/block-size-with-min-or-max-content-table-1b.html [ Pass Failure ]
+crbug.com/918905 [ Mac Linux ] external/wpt/css/vendor-imports/mozilla/mozilla-central-reftests/sizing/block-size-with-min-or-max-content-table-1b.html [ Pass Failure ]