Enable stack-walking for default coroutine names

If coroutine does not have a trace name, walk the stack to infer a name
for it.

Test: Capture trace, look for coroutine IDs
Flag: com.android.systemui.coroutine_tracing
Bug: 289353932
Change-Id: I9e04098e69d12cc06b4c1dd29528f760ffeb26f8