[dev.link] cmd/link: set "local" attribute on symbols during preload
[dev.link] cmd/link: set "local" attribute on symbols during preload

Set the "local" attribute on object file loader symbols during preload,
as opposed to the current strategy of only propagating the local attr
when we convert to sym.Symbols.

Change-Id: I18965e2fdaa9a0b9315d95466d17d9f41aa40a45
Reviewed-on: https://go-review.googlesource.com/c/go/+/224379
Run-TryBot: Than McIntosh <4b2922593166fc595a9b1a408f34f5d3817fe9d2@google.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Jeremy Faller <b3f594e10a9edcf5413cf1190121d45078c62290@golang.org>
Reviewed-by: Cherry Zhang <d62e63aa42ce272d7b6a5055d97e942b33a34679@google.com>

golang/go,CAFxX/go,nawawi/go,akutz/go,golang/go,golang/go,akutz/go,CAFxX/go,akutz/go,golang/go,cloudflare/go,golang/go,nawawi/go,akutz/go,cloudflare/go,cloudflare/go,CAFxX/go,cloudflare/go,nawawi/go,cloudflare/go,CAFxX/go,nawawi/go,nawawi/go,CAFxX/go,akutz/go,cloudflare/go,akutz/go,CAFxX/go,golang/go,akutz/go,akutz/go,nawawi/go,CAFxX/go,cloudflare/go,cloudflare/go,nawawi/go,nawawi/go,golang/go,CAFxX/go,golang/go