runtime: don't track stack separately in gentraceback
Currently, gentraceback keeps a copy of the stack bounds of the stack
it's walking in the "stack" variable. Now that "gp" always refers to
the G whose stack it's walking, we can simply use gp.stack instead of
keeping a separate copy.
For #54466.
Change-Id: I68256e5dff6212cfcf14eda615487e66a92d4914
Reviewed-on: https://go-review.googlesource.com/c/go/+/458215
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Felix Geisendörfer <felix.geisendoerfer@datadoghq.com>
TryBot-Result: Gopher Robot <gobot@golang.org>