cmd/go: fix TestNewReleaseRebuildsStalePackagesInGOPATH for runtime move

CL 600436 moved runtime/internal/sys to internal/runtime/sys and updated
TestNewReleaseRebuildsStalePackagesInGOPATH in part accordingly. This is
the other part that's needed for it to pass.

For #65355.

Change-Id: I26cff96c15caf185a4ee2c8fb31ec6c877ab87e2
Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64-longtest
Reviewed-on: https://go-review.googlesource.com/c/go/+/600595
Reviewed-by: Dmitri Shuralyov <[email protected]>
Auto-Submit: Dmitri Shuralyov <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: David Chase <[email protected]>

Author: dmitshur

src/cmd/go/go_test.go

@@ -957,17 +957,17 @@ func TestNewReleaseRebuildsStalePackagesInGOPATH(t *testing.T) {
 	// now they all matter, so keep using sys.go.
 	restore = addVar(sys, 1)
 	defer restore()
-	tg.wantStale("p1", "stale dependency: runtime/internal", "./testgo list claims p1 is NOT stale, incorrectly, after changing sys.go")
+	tg.wantStale("p1", "stale dependency: internal/runtime/sys", "./testgo list claims p1 is NOT stale, incorrectly, after changing sys.go")
 	restore()
 	tg.wantNotStale("p1", "", "./testgo list claims p1 is stale, incorrectly, after changing back to old release")
 	addVar(sys, 2)
-	tg.wantStale("p1", "stale dependency: runtime", "./testgo list claims p1 is NOT stale, incorrectly, after changing sys.go again")
+	tg.wantStale("p1", "stale dependency: internal/runtime/sys", "./testgo list claims p1 is NOT stale, incorrectly, after changing sys.go again")
 	tg.run("install", "p1")
 	tg.wantNotStale("p1", "", "./testgo list claims p1 is stale after building with new release")
 
 	// Restore to "old" release.
 	restore()
-	tg.wantStale("p1", "stale dependency: runtime/internal", "./testgo list claims p1 is NOT stale, incorrectly, after restoring sys.go")
+	tg.wantStale("p1", "not installed but available in build cache", "./testgo list claims p1 is NOT stale, incorrectly, after restoring sys.go")
 	tg.run("install", "p1")
 	tg.wantNotStale("p1", "", "./testgo list claims p1 is stale after building with old release")
 }