io/fs: remove darwin/arm64 special condition

It isn't necessary on darwin/arm64 (macOS).

It was probably leftover from the old code when darwin/arm64
meant iOS. The test passes on iOS builder. Apparently this is
not needed either. Remove.

Change-Id: I6fa0c55d6086325d4b722862c4fe6c30bcd6e6e8
Reviewed-on: https://go-review.googlesource.com/c/go/+/280158
Trust: Cherry Zhang <[email protected]>
Run-TryBot: Cherry Zhang <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>

Author: cherrymui

src/io/fs/walk_test.go

@@ -9,7 +9,6 @@ import (
 	"io/ioutil"
 	"os"
 	pathpkg "path"
-	"runtime"
 	"testing"
 	"testing/fstest"
 )
@@ -96,32 +95,7 @@ func mark(entry DirEntry, err error, errors *[]error, clear bool) error {
 	return nil
 }
 
-func chtmpdir(t *testing.T) (restore func()) {
-	oldwd, err := os.Getwd()
-	if err != nil {
-		t.Fatalf("chtmpdir: %v", err)
-	}
-	d, err := ioutil.TempDir("", "test")
-	if err != nil {
-		t.Fatalf("chtmpdir: %v", err)
-	}
-	if err := os.Chdir(d); err != nil {
-		t.Fatalf("chtmpdir: %v", err)
-	}
-	return func() {
-		if err := os.Chdir(oldwd); err != nil {
-			t.Fatalf("chtmpdir: %v", err)
-		}
-		os.RemoveAll(d)
-	}
-}
-
 func TestWalkDir(t *testing.T) {
-	if runtime.GOOS == "darwin" && runtime.GOARCH == "arm64" {
-		restore := chtmpdir(t)
-		defer restore()
-	}
-
 	tmpDir, err := ioutil.TempDir("", "TestWalk")
 	if err != nil {
 		t.Fatal("creating temp dir:", err)