Remove obsolete SPDY test exclusions.

SpdyNetworkTransactionSpdy*Test has been removed in https://crrev.com/16816010.
SpdyHttpStreamSpdy*Test has been removed in https://crrev.com/17004007.  These
two exclusions are now obsolete.

BUG=118883
NOTRY=true

Review URL: https://codereview.chromium.org/579463002

Cr-Commit-Position: refs/heads/master@{#295106}

tools/valgrind/gtest_exclude/net_unittests.gtest.txt

@@ -9,10 +9,6 @@ DirectoryListerTest.BigDirRecursiveTest
 SSLClientSocketTest.Connect
 SSLClientSocketTest.ConnectClientAuthSendNullCert
 
-# These tests are broken http://crbug.com/118883
-*SpdyNetworkTransactionSpdy*Test.*
-*SpdyHttpStreamSpdy*Test.*
-
 # Fails flakily. http://crbug.com/255775
 SimpleIndexFileTest.WriteThenLoadIndex