Revert "Blacklist failing libcore tests."

This reverts commit fb7658b728690592938dfedc57231ade4e7bd870.

Fixed by commit 856bdfb2bd47e91950182d0c1427944e8e2ab771

Change-Id: I5977cc63f867c51c62de61dbed64cdb444d0dfbf
bug: 30917411
test: run cts -c org.apache.harmony.tests.java.math.BigIntegerTest
diff --git a/tools/libcore_failures.txt b/tools/libcore_failures.txt
index 6472c8d..a69b58b 100644
--- a/tools/libcore_failures.txt
+++ b/tools/libcore_failures.txt
@@ -234,15 +234,5 @@
   modes: [device],
   names: ["libcore.java.lang.ProcessBuilderTest#testRedirectInherit",
           "libcore.java.lang.ProcessBuilderTest#testRedirect_nullStreams"]
-},
-{
-  description: "BigInteger failures due to the BoringSSL upgrade",
-  result: EXEC_FAILED,
-  bug: 30917411,
-  names: [
-    "org.apache.harmony.tests.java.math.BigIntegerModPowTest#testModPowNegExp",
-    "org.apache.harmony.tests.java.math.BigIntegerModPowTest#testmodInversePos1",
-    "org.apache.harmony.tests.java.math.BigIntegerTest#test_modInverseLjava_math_BigInteger"
-  ]
 }
 ]