vndk-def: Add --system-dir-ignored option

This commit adds --system-dir-ignored option so that the user can
ignore /system/vendor directory and run the following command on some
devices:

    python3 vndk_definition_tool.py vndk \
      --system ${ANDROID_PRODUCT_OUT}/system \
      --system-dir-ignored vendor \
      --vendor ${ANDROID_PRODUCT_OUT}/vendor

Test: ./tests/run.py
Test: Add --system-dir-ignored to make sure /system/vendor on some
devices are not treated as system modules.

Change-Id: I45a82bf81f2e2a6b34c146310f53d47dfe2313c3
2 files changed