[dev.link] cmd/link: stop loading FuncInfo in LoadFull

As we have converted the pclntab generation, FuncInfo is not
needed after. No need to load it.

Change-Id: Idcfe4da44dfc94d8d44509d12179b354a2e295e9
Reviewed-on: https://go-review.googlesource.com/c/go/+/228139


Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>