add virtual device known failures expectation file

* the file contains tests known to fail on virtual devices, due
  to limitation of its test infra setup

Bug: 30965313
Bug: 31429663
Test: ...
  $ unzip -l \
    out/host/linux-x86/cts/android-cts/testcases/CtsLibcoreTestCases.apk \
    | grep virtualdevice # check for existence
  BEFORE: $ cts-tradefed run collect-tests-only \
    --include-filter CtsLibcoreTestCases
  AFTER: $ cts-tradefed run collect-tests-only \
    --include-filter CtsLibcoreTestCases \
    --compatibility:module-arg \
    CtsLibcoreTestCases:core-expectation:/virtualdeviceknownfailures.txt
  Compare generated test list to make sure listed test is excluded

Change-Id: I0bbe0acbf2823429b831c0a33475fe297c338c9a
diff --git a/expectations/virtualdeviceknownfailures.txt b/expectations/virtualdeviceknownfailures.txt
new file mode 100644
index 0000000..f427a71
--- /dev/null
+++ b/expectations/virtualdeviceknownfailures.txt
@@ -0,0 +1,11 @@
+/*
+ * This file contains expectations for tests known to fail on virtual device
+ */
+[
+{
+  description: "IPv6 connectivity not yet supported in virtual device testing infra",
+  result: EXEC_FAILED,
+  name: "libcore.java.net.SocketTest#testSocketTestAllAddresses",
+  bug: 30965313
+}
+]