add Android test suite

Xref #1701 (closed)

The plan for adding a test suite is to cross-compile, adb push the whole build dir over, and prepend "adb shell" to all of the test commands, thus running ctest itself from the host. (It would not be easy to try and get a version of ctest built to run natively on Android as we would have to custom-build many system libraries that it uses.)