Adding handling for KeyUpdate post-handshake message.

BUG=74

Change-Id: I72d52c1fbc3413e940dddbc0b20c7f22459da693
Reviewed-on: https://boringssl-review.googlesource.com/8981
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/ssl/test/runner/runner.go b/ssl/test/runner/runner.go
index 48d8703..ccd25d4 100644
--- a/ssl/test/runner/runner.go
+++ b/ssl/test/runner/runner.go
@@ -2166,6 +2166,16 @@
 			shouldFail:    true,
 			expectedError: ":WRONG_VERSION_NUMBER:",
 		},
+		{
+			testType: clientTest,
+			name:     "KeyUpdate",
+			config: Config{
+				MaxVersion: VersionTLS13,
+				Bugs: ProtocolBugs{
+					SendKeyUpdateBeforeEveryAppDataRecord: true,
+				},
+			},
+		},
 	}
 	testCases = append(testCases, basicTests...)
 }