os: do not test Lstat in TestDevNullFile

CL 102456 added Lstat check to TestDevNullFile.
But some systems have /dev/null as a symlink,
so Lstat test is wrong. Remove the test.

Fixes #24521

Change-Id: I149110b08dd05db6495ec4eccbcf943e444332f9
Reviewed-on: https://go-review.googlesource.com/102461
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/os/os_test.go

@@ -1835,12 +1835,6 @@ func testDevNullFile(t *testing.T, devNullName string, ignoreCase bool) {
 		t.Fatalf("Stat(%s): %v", devNullName, err)
 	}
 	testDevNullFileInfo(t, "Stat", devNullName, fi, ignoreCase)
-
-	fi, err = Lstat(devNullName)
-	if err != nil {
-		t.Fatalf("Lstat(%s): %v", devNullName, err)
-	}
-	testDevNullFileInfo(t, "Lstat", devNullName, fi, ignoreCase)
 }
 
 func TestDevNullFile(t *testing.T) {