Revert "Temporarily disable failing libcore tests (caused by mockito merge)."

This reverts commit 4c9b493083cebae58c067642b7a85d93df7a95b0.

Reason for revert: The mockito issue has been fixed.

Test: Ran libcore.java.lang test locally
Change-Id: Iad88ef2a09348a759c3e942a5d06e4e2a4556ced
diff --git a/tools/libcore_failures.txt b/tools/libcore_failures.txt
index 3ef78d5..d83c522 100644
--- a/tools/libcore_failures.txt
+++ b/tools/libcore_failures.txt
@@ -216,16 +216,6 @@
   names: ["libcore.javax.crypto.spec.AlgorithmParametersTestGCM#testEncoding"]
 },
 {
-  description: "Tests fail because mockito can not read android.os.Build$VERSION",
-  result: EXEC_FAILED,
-  bug: 111704422,
-  names: ["libcore.java.lang.ThreadTest#testUncaughtExceptionPreHandler_calledBeforeDefaultHandler",
-          "libcore.java.lang.ThreadTest#testUncaughtExceptionPreHandler_noDefaultHandler",
-          "libcore.javax.crypto.CipherInputStreamTest#testCloseTwice",
-          "libcore.libcore.io.BlockGuardOsTest#test_android_getaddrinfo_networkPolicy",
-          "libcore.libcore.io.BlockGuardOsTest#test_checkNewMethodsInPosix"]
-},
-{
   description: "fdsan doesn't exist on the host",
   result: EXEC_FAILED,
   modes: [host],