[dev.typeparams] runtime: use internal/abi.FuncPCABI0 for sigtramp PC on FreeBSD

Same as CL 313230, for FreeBSD. sigtramp is the only one we need.

Change-Id: Iefc00c1cb7e70b08a07c3bc3604b2114fd86563d
Reviewed-on: https://go-review.googlesource.com/c/go/+/320912


Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>