Pull in relevant targets when using xcode-ninja
The tests gyptest-actions, gyptest-copies and gyptest-rules fail when
using the xcode-ninja generator because xcode-ninja (by design) only
creates targets for proper executables. In order for these three tests
to pass, the targets they rely on need to be included explicitly.
./gyptest.py -f xcode-ninja test/generator-output/
Expected: all tests pass (instead of failing the three mentioned above).