Add redundant com.android.org.conscrypt tests to knownfailures

The the android.keystore tests validates the codepath more properly

Bug: 18030049
Change-Id: I2ffcb313fc18baf33bd2fa45ca69137d7df4bd6b
diff --git a/tests/expectations/knownfailures.txt b/tests/expectations/knownfailures.txt
index d931855..2d2d460 100644
--- a/tests/expectations/knownfailures.txt
+++ b/tests/expectations/knownfailures.txt
@@ -361,5 +361,14 @@
     "android.uirendering.cts.testclasses.FontRenderingTests"
   ],
   bug: 17109280
+},
+{
+  description: "android.keystore tests will replace these tests",
+  names: [
+    "com.android.org.conscrypt.MacTest#test_getInstance_OpenSSL_ENGINE",
+    "com.android.org.conscrypt.NativeCryptoTest#test_ENGINE_by_id_TestEngine",
+    "com.android.org.conscrypt.SignatureTest#test_getInstance_OpenSSL_ENGINE"
+  ],
+  bug: 18030049
 }
 ]