all: update _test.go files for ioutil changes

transform/allocs_test.go

@@ -2,7 +2,7 @@ package transform_test
 
 import (
 	"go/token"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"regexp"
 	"sort"
@@ -62,7 +62,7 @@ func TestAllocs2(t *testing.T) {
 	}
 
 	// Load expected test output (the OUT: lines).
-	testInput, err := ioutil.ReadFile("./testdata/allocs2.go")
+	testInput, err := os.ReadFile("./testdata/allocs2.go")
 	if err != nil {
 		t.Fatal("could not read test input:", err)
 	}

transform/transform_test.go

@@ -6,7 +6,6 @@ import (
 	"flag"
 	"go/token"
 	"go/types"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -58,13 +57,13 @@ func testTransform(t *testing.T, pathPrefix string, transform func(mod llvm.Modu
 	actual = actual[strings.Index(actual, "\ntarget datalayout = ")+1:]
 
 	if *update {
-		err := ioutil.WriteFile(pathPrefix+".out.ll", []byte(actual), 0666)
+		err := os.WriteFile(pathPrefix+".out.ll", []byte(actual), 0666)
 		if err != nil {
 			t.Error("failed to write out new output:", err)
 		}
 	} else {
 		// Read the expected output IR.
-		out, err := ioutil.ReadFile(pathPrefix + ".out.ll")
+		out, err := os.ReadFile(pathPrefix + ".out.ll")
 		if err != nil {
 			t.Fatalf("could not read output file %s: %v", pathPrefix+".out.ll", err)
 		}