internal/socket, webdav: use testing.T.TempDir

It's available since Go 1.15 and go.mod currently specifies Go 1.18.

Change-Id: Ia5ba22f5802f4af9fb6d3b6e7ee5a02ce3582e9a
Reviewed-on: https://go-review.googlesource.com/c/net/+/643595
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

internal/socket/socket_test.go

diff --git a/internal/socket/socket_test.go b/internal/socket/socket_test.go
index 44c196b..26077a7 100644
--- a/internal/socket/socket_test.go
+++ b/internal/socket/socket_test.go
@@ -445,11 +445,7 @@
 	if runtime.Compiler == "gccgo" {
 		t.Skip("skipping race test when built with gccgo")
 	}
-	dir, err := os.MkdirTemp("", "testrace")
-	if err != nil {
-		t.Fatalf("failed to create temp directory: %v", err)
-	}
-	defer os.RemoveAll(dir)
+	dir := t.TempDir()
 	goBinary := filepath.Join(runtime.GOROOT(), "bin", "go")
 	t.Logf("%s version", goBinary)
 	got, err := exec.Command(goBinary, "version").CombinedOutput()

webdav/file_test.go

diff --git a/webdav/file_test.go b/webdav/file_test.go
index 3af53fd..c9313dc 100644
--- a/webdav/file_test.go
+++ b/webdav/file_test.go
@@ -517,12 +517,7 @@
 		t.Skip("see golang.org/issue/11453")
 	}
 
-	td, err := os.MkdirTemp("", "webdav-test")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.RemoveAll(td)
-	testFS(t, Dir(td))
+	testFS(t, Dir(t.TempDir()))
 }
 
 func TestMemFS(t *testing.T) {