cmd/go: convert TestGoTestRaceInstallsCgo to script framework

Part of converting all tests to script framework to improve
test parallelism.

Updates #36320
Updates #17751

Change-Id: I9a99aa5d37300c83a2f95fb906949cb4c1d5356f
Reviewed-on: https://go-review.googlesource.com/c/go/+/214426
Reviewed-by: Jay Conrod <jayconrod@google.com>

src/cmd/go/go_test.go

@@ -2013,37 +2013,6 @@ func TestGoInstallPkgdir(t *testing.T) {
 	tg.mustExist(filepath.Join(pkg, "sync/atomic.a"))
 }
 
-func TestGoTestRaceInstallCgo(t *testing.T) {
-	if !canRace {
-		t.Skip("skipping because race detector not supported")
-	}
-
-	// golang.org/issue/10500.
-	// This used to install a race-enabled cgo.
-	tg := testgo(t)
-	defer tg.cleanup()
-	tg.run("tool", "-n", "cgo")
-	cgo := strings.TrimSpace(tg.stdout.String())
-	old, err := os.Stat(cgo)
-	tg.must(err)
-
-	// For this test, we don't actually care whether 'go test -race -i' succeeds.
-	// It may fail, for example, if GOROOT was installed from source as root and
-	// is now read-only.
-	// We only care that — regardless of whether it succeeds — it does not
-	// overwrite cmd/cgo.
-	runArgs := []string{"test", "-race", "-i", "runtime/race"}
-	if status := tg.doRun(runArgs); status != nil {
-		tg.t.Logf("go %v failure ignored: %v", runArgs, status)
-	}
-
-	new, err := os.Stat(cgo)
-	tg.must(err)
-	if !new.ModTime().Equal(old.ModTime()) {
-		t.Fatalf("go test -i runtime/race reinstalled cmd/cgo")
-	}
-}
-
 func TestGoInstallShadowedGOPATH(t *testing.T) {
 	// golang.org/issue/3652.
 	// go get foo.io (not foo.io/subdir) was not working consistently.

src/cmd/go/testdata/script/test_race_install_cgo.txt

@@ -0,0 +1,91 @@
+# Tests Issue #10500
+
+[!race] skip
+
+env GOBIN=$WORK/bin
+go install mtime sametime
+
+go tool -n cgo
+cp stdout cgopath.txt
+exec $GOBIN/mtime cgopath.txt # get the mtime of the file whose name is in cgopath.txt
+cp stdout cgotime_before.txt
+
+ # For this test, we don't actually care whether 'go test -race -i' succeeds.
+ # It may fail, for example, if GOROOT was installed from source as root and
+ # is now read-only.
+ # We only care that — regardless of whether it succeeds — it does not
+ # overwrite cmd/cgo.
+go test -race -i runtime/race
+
+exec $GOBIN/mtime cgopath.txt # get the mtime of the file whose name is in cgopath.txt
+cp stdout cgotime_after.txt
+exec $GOBIN/sametime cgotime_before.txt cgotime_after.txt
+
+-- mtime/mtime.go --
+package main
+
+import (
+	"io/ioutil"
+	"encoding/json"
+	"fmt"
+	"os"
+	"strings"
+)
+
+func main() {
+	b, err := ioutil.ReadFile(os.Args[1])
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	filename := strings.TrimSpace(string(b))
+	info, err := os.Stat(filename)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	if err := json.NewEncoder(os.Stdout).Encode(info.ModTime()); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+-- sametime/sametime.go --
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"time"
+)
+
+
+func main() {
+	var t1 time.Time
+	b1, err := ioutil.ReadFile(os.Args[1])
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	if err := json.Unmarshal(b1, &t1); err != nil  {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	var t2 time.Time
+	b2, err := ioutil.ReadFile(os.Args[2])
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	if err := json.Unmarshal(b2, &t2); err != nil  {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	if !t1.Equal(t2) {
+		fmt.Fprintf(os.Stderr, "time in %v (%v) is not the same as time in %v (%v)", os.Args[1], t1, os.Args[2], t2)
+		os.Exit(1)
+	}
+}