Revert "cmd/go: use platform.MustLinkExternal in externalLinkingForced"

This reverts CL 477395.

Failing on darwin-amd64 builders:
https://build.golang.org/log/b07ec5e40a896f5d099e4c85f4094321ecc84f21

loadinternal: cannot find runtime/cgo
signal: trace/BPT trap
FAIL	crypto/x509	0.024s
FAIL
2023/03/20 12:16:35 Failed: exit status 1

Change-Id: Ib9923f9ff7e24c3b5f8690ba1d6b5d0b6693d49c
Reviewed-on: https://go-review.googlesource.com/c/go/+/477736
TryBot-Result: Gopher Robot <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>

Author: ianlancetaylor

src/cmd/go/internal/load/pkg.go

@@ -2606,7 +2606,12 @@ func externalLinkingForced(p *Package) bool {
 	}
 
 	// Some targets must use external linking even inside GOROOT.
-	if platform.MustLinkExternal(cfg.BuildContext.GOOS, cfg.BuildContext.GOARCH, false) {
+	switch cfg.BuildContext.GOOS {
+	case "android":
+		if cfg.BuildContext.GOARCH != "arm64" {
+			return true
+		}
+	case "ios":
 		return true
 	}