Now that we plumb the start line to the runtime, we can include in pprof
files. Since runtime.Frame.startLine is not (currently) exported, we
need a runtime helper to get the value.
For #55022.
Updates #56135.
Change-Id: Ifc5b68a7b7170fd7895e4099deb24df7977b22ea
Reviewed-on: https://go-review.googlesource.com/c/go/+/438255
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com> Reviewed-by: Austin Clements <austin@google.com>