Add a feature flag for CTS.

Bug: 36599543
Test: Build sailfish and CTS
Test: run cts -o -m CtsAppTestCases -t android.app.cts.SystemFeaturesTest#testFeatureNamespaces
Change-Id: I659ddbe7d6e2d8762d97b8a418cfc246f7a97a3e
1 file changed