tools/clang/blink_gc_plugin/tests/cycle_sub.txt

Found a potentially leaking cycle starting from a GC root:
./cycle_sub.h:31:5:  blink::C (m_a) => blink::A
./cycle_sub.h:22:11: blink::A (<subclass>) => blink::B
./cycle_sub.h:26:5:  blink::B (m_c) => blink::C