[SPDY] Fix flaky SpdyNetworkTransactionTest.WriteError unit test

Use DeterministicSocketData instead of DelayedSocketData, which avoids
the possibility of flakiness entirely.

BUG=299653
R=rch@chromium.org

Review URL: https://codereview.chromium.org/27597003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229017 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229017