runtime: add mayAcquire annotation for trace.lock
Now that we've moved the trace locks to the leaf of the lock graph, we
can safely annotate that any trace event may acquire trace.lock even
if dynamically it turns out a particular event doesn't need to flush
and acquire this lock.
This reveals a new edge where we can trace while holding the mheap
lock, so we add this to the lock graph.
For #53789.
Updates #53979.
Change-Id: I13e2f6cd1b621cca4bed0cc13ef12e64d05c89a7
Reviewed-on: https://go-review.googlesource.com/c/go/+/418720
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>