sourcedr: Add list_ninja_build_dep.py to list deps

This commit adds `list_ninja_build_dep.py` to list the transitive ninja
build rules of a given target.

Test: ./list_ninja_build_dep.py graph.pickle systemimage > out.txt
Change-Id: I423247d83f9bccad8db98c29b88f8c9ba72cc671
1 file changed