cmd/go/internal/load,cmd/link/internal/ld: use objabi.LookupPkgSpecial(pkg).Runtime

As suggested by Michael in CL 655515.

Change-Id: I472d32da835757abfd4448b142a033aa9ca3e40b

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

@@ -7,6 +7,7 @@ package load
 
 import (
 	"bytes"
+	"cmd/internal/objabi"
 	"context"
 	"encoding/json"
 	"errors"
@@ -3561,7 +3562,7 @@ func SelectCoverPackages(roots []*Package, match []func(*Package) bool, op strin
 		// $GOROOT/src/internal/coverage/pkid.go dealing with
 		// hard-coding of runtime package IDs.
 		cmode := cfg.BuildCoverMode
-		if cfg.BuildRace && p.Standard && p.ImportPath == "runtime" {
+		if cfg.BuildRace && p.Standard && objabi.LookupPkgSpecial(p.ImportPath).Runtime {
 			cmode = "regonly"
 		}
 

src/cmd/link/internal/ld/data.go

@@ -55,30 +55,8 @@ import (
 )
 
 // isRuntimeDepPkg reports whether pkg is the runtime package or its dependency.
-// TODO: just compute from the runtime package, and remove this hardcoded list.
 func isRuntimeDepPkg(pkg string) bool {
-	switch pkg {
+	return objabi.LookupPkgSpecial(pkg).Runtime
-	case "runtime",
-		"sync/atomic",  // runtime may call to sync/atomic, due to go:linkname // TODO: this is not true?
-		"internal/abi", // used by reflectcall (and maybe more)
-		"internal/asan",
-		"internal/bytealg", // for IndexByte
-		"internal/byteorder",
-		"internal/chacha8rand", // for rand
-		"internal/coverage/rtcov",
-		"internal/cpu", // for cpu features
-		"internal/goarch",
-		"internal/godebugs",
-		"internal/goexperiment",
-		"internal/goos",
-		"internal/msan",
-		"internal/profilerecord",
-		"internal/race",
-		"internal/stringslite",
-		"unsafe":
-		return true
-	}
-	return strings.HasPrefix(pkg, "internal/runtime/") && !strings.HasSuffix(pkg, "_test")
 }
 
 // Estimate the max size needed to hold any new trampolines created for this function. This