[release-branch.go1.19] os: skip size test in TestLstat if the file i…

…s a symlink

Tested by temporarily changing sysdir to use a directory where
the expected files were all symlinks. We should consider using
a different approach that doesn't rely on sysdir, but for now
do a minimal fix.

For #57210
Fixes #57214

Change-Id: Ifb1becef03e014ceb48290ce13527b3e103c0e07
Reviewed-on: https://go-review.googlesource.com/c/go/+/456557
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
(cherry picked from commit 9b8750f)
Reviewed-on: https://go-review.googlesource.com/c/go/+/456560
Reviewed-by: Austin Clements <austin@google.com>

src/os/os_test.go

@@ -275,9 +275,11 @@ func TestLstat(t *testing.T) {
 	if !equal(sfname, dir.Name()) {
 		t.Error("name should be ", sfname, "; is", dir.Name())
 	}
-	filesize := size(path, t)
-	if dir.Size() != filesize {
-		t.Error("size should be", filesize, "; is", dir.Size())
+	if dir.Mode()&ModeSymlink == 0 {
+		filesize := size(path, t)
+		if dir.Size() != filesize {
+			t.Error("size should be", filesize, "; is", dir.Size())
+		}
 	}
 }