fuchsia: Disable some flaking tests in base, content, net

TBR: wez@chromium.org
Bug: 784448, 784449
Change-Id: I06d0473968ae2dbdb9c480cf58b25ba1fbc2a764
Reviewed-on: https://chromium-review.googlesource.com/766152Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515979}

testing/buildbot/filters/fuchsia.base_unittests.filter

@@ -40,6 +40,7 @@
 # pretty confident you've fixed their rarely-flakiness before re-enabling.
 -AllModes/TaskSchedulerSingleThreadTaskRunnerManagerCommonTest.*
 -AllocationRegisterTest.InsertRemoveRandomOrder
+-ConditionVariableTest.MultiThreadConsumerTest
 -MemoryPeakDetectorTest.StdDev
 -MemoryPeakDetectorTest.Throttle
 -ObserverListThreadSafeTest.CrossThreadObserver

testing/buildbot/filters/fuchsia.content_unittests.filter

@@ -55,3 +55,6 @@
 
 # Flaky: https://crbug.com/780508.
 -ServiceWorkerProviderHostTest.*
+
+# Flaky, https://crbug.com/784449.
+-WebContentsAudioInputStreamTest.MirroringOneStreamAfterTargetChange*

testing/buildbot/filters/fuchsia.net_unittests.filter

@@ -14,3 +14,6 @@
 # These stress tests take a very long time on emulated ARM cores.
 -SupportedVersion/QuicConnectionTest.TooManySentPackets/*
 -RangeOfTreeSizes/CTLogVerifierTestUsingGenerator.VerifiesValidConsistencyProof/*
+
+# Flaky, https://crbug.com/784448.
+-DiskCacheBackendTest.InvalidEntry5