fuchsia: disable MemoryDumpSchedulerTest pending crbug.com/751748

TBR=wez@chromium.org

Bug: 751748, 738275
Change-Id: I775792a7441dca5fd90e410653cba4610115780a
Reviewed-on: https://chromium-review.googlesource.com/599187
Commit-Queue: Scott Graham <scottmg@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491615}

testing/buildbot/filters/fuchsia.base_unittests.filter

@@ -75,9 +75,12 @@
 -VerifyPathControlledByUserTest.Symlinks
 -VerifyPathControlledByUserTest.WriteBitChecks
 
-# CancelableSyncSocket tests fail: http://crbug.com/741783
+# CancelableSyncSocket tests fail: https://crbug.com/741783
 -CancelableSyncSocket*
 
+# Likely flake cause identified, disabled pending fix: https://crbug.com/751748.
+-MemoryDumpSchedulerTest.*
+
 # These tests are occasionally flaking. See https://crbug.com/738275. Please be
 # pretty confident you've fixed their rarely-flakiness before re-enabling.
 -AllModes/TaskSchedulerSingleThreadTaskRunnerManagerCommonTest.*