Revert "Disable a pair of NetworkContextConfigurationBrowserTests."

This reverts commit 6dc3ae616d065090e4f9004f4acc4f743794cf60.

Reason for revert: Turns out there's a new flaky test suite, which
should probably be disabled instead.

Original change's description:
> Disable a pair of NetworkContextConfigurationBrowserTests.
> 
> They are flaky on "non_single_process_mash_browser_tests", likely due
> to https://chromium-review.googlesource.com/c/chromium/src/+/1443733.
> 
> These look like races with network configuration changes, so are not
> real bugs.
> 
> NOTRY=true
> TBR=asanka@chromium.org
> 
> Bug: 928685
> Change-Id: I0a6ff4df635b26af56e1c8fd60ad2bc4c1525372
> Reviewed-on: https://chromium-review.googlesource.com/c/1454124
> Reviewed-by: Matt Menke <mmenke@chromium.org>
> Commit-Queue: Matt Menke <mmenke@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#629137}

TBR=mmenke@chromium.org,asanka@chromium.org

Change-Id: Ib364816ba460980512adeac805ef0789b286756f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 928685
Reviewed-on: https://chromium-review.googlesource.com/c/1455026
Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#629236}
1 file changed