Option for Running Known Failures

Since knownfailures.txt is required by the build system, we cannot
simply delete the file to run known failures. Therefore add a
"run-known-failures" option to run even known failures.

The XML Generator now writes even known failures but adds
expectation="failure" to indicate that the test is expected to fail.
Then TestPackageXmlParser will only include these tests like a
normal test if "run-known-failures" has been set.

CtsConsole builds a TestPackageRepo but doesn't have simple
access to the flag value, so just assume known failures are not
included. This should be ok, because it only uses a TestPackageRepo
to list the packages.

Change-Id: Ie77c8b3f69c2164cffa7d231e357e52338b21dad
8 files changed