vndk-def: Collect non-AOSP libs must be copied

This commit collects all non-AOSP system libraries that are used by
vendor modules and add them to vndk-ext so that they are copied into
vendor partition.

Bug: 37867089
Test: Some vendor HIDL interface libs are tagged with vndk-ext given
sailfish images.

Change-Id: I77d8f66d97b403991593d5b1f88573411e96d679