os: avoid TestFileChdir fail when GOROOT is a symbolic link

If GOROOT is a symbolic link,
the paths obtained from the
first and second Getwd of TestFileChdir are different,
and this CL fixes the test failure in this situation.

Fixes #64281

Change-Id: I53026b6c54a54be08833396e2c7081ca3ab8c282
GitHub-Last-Rev: 5cc418e
GitHub-Pull-Request: #64001
Reviewed-on: https://go-review.googlesource.com/c/go/+/540521
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

Author: qiulaidongfeng

src/os/os_test.go

@@ -1620,8 +1620,17 @@ func TestFileChdir(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Getwd: %s", err)
 	}
-	if !equal(wdNew, wd) {
-		t.Fatalf("fd.Chdir failed, got %s, want %s", wdNew, wd)
+
+	wdInfo, err := fd.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+	newInfo, err := Stat(wdNew)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !SameFile(wdInfo, newInfo) {
+		t.Fatalf("fd.Chdir failed: got %s, want %s", wdNew, wd)
 	}
 }