cmd/link: require cgo support for TestSectionsWithSameName
cmd/link: require cgo support for TestSectionsWithSameName

The test doesn't really require cgo, but it does require that we know
the right flags to use to run the C compiler, and that is not
necessarily correct if we don't support cgo.

Fixes #31565

Change-Id: I04dc8db26697caa470e91ad712376aa621cf765d
Reviewed-on: https://go-review.googlesource.com/c/go/+/172981
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

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