runtime: symbolize wrappers as a last resort in race tracebacks
CL 466099 rewrote stack symbolization in race reports. Prior to this
CL, physical frames consisting entirely of wrapper logical frame would
print the wrapper, even though in other cases we try to avoid
printing wrappers. CL 466099 unintentionally changed this behavior and
now physical frames consisting entirely of wrapper frames instead fail
to symbolize and print "??()".
Fix this by taking the outermost wrapper frame if the entire logical
frame expansion consists of wrappers.
Fixes #60245.
Change-Id: I13de8857e508b757ea10d1fc7a47258d7fddbfdb
Reviewed-on: https://go-review.googlesource.com/c/go/+/497235
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
Auto-Submit: Austin Clements <austin@google.com>