Disable failing content_browsertests with Network Service

These tests recently started to fail with the Network Service enabled.

TBR=qinmin@chromium.org
NOTRY=true

Bug: 715630
Change-Id: Ic36c83567eda25423987d7b63d7bff1f10e7990d
Reviewed-on: https://chromium-review.googlesource.com/723673Reviewed-by: Reilly Grant <reillyg@chromium.org>
Commit-Queue: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509499}

testing/buildbot/filters/mojo.fyi.network_content_browsertests.filter

@@ -59,6 +59,13 @@
 -DownloadContentTest.RestartIfNoPartialFile
 -DownloadContentTest.RestartIfNotPartialResponse
 -DownloadContentTest.Resume_Hash
+-DownloadContentTest.ResumeRestoredDownload_CorrectHash
+-DownloadContentTest.ResumeRestoredDownload_EtagMismatch
+-DownloadContentTest.ResumeRestoredDownload_LongFile
+-DownloadContentTest.ResumeRestoredDownload_NoFile
+-DownloadContentTest.ResumeRestoredDownload_NoHash
+-DownloadContentTest.ResumeRestoredDownload_ShortFile
+-DownloadContentTest.ResumeRestoredDownload_WrongHash
 -DownloadContentTest.ShutdownAtRelease
 -DownloadContentTest.ShutdownInProgress
 -DownloadContentTest.SniffedMimeType
@@ -122,6 +129,9 @@
 -NavigationControllerBrowserTest.RefererStoredForSubFrame
 -NavigationControllerBrowserTest.BackSameDocumentAfterBlockedSubframe
 -NavigationHandleImplBrowserTest.ErrorCodeOnRedirect
+-NavigationHandleImplBrowserTest.VerifyCertErrorFailure
+-NavigationHandleImplBrowserTest.ThrottleDeferFailure
+-NavigationHandleImplBrowserTest.ThrottleCancelFailure
 -NavigationHandleImplBrowserTest.RedirectToRendererDebugUrl
 -PlzNavigateNavigationHandleImplBrowserTest.ErrorPageNetworkError
 -PowerMonitorTest.TestGpuProcess