Revert "Handle symlinks in sbox"

This reverts commit dd9529050d0ef329cec4ea6c426e9c134c6055c5.

Reason for revert: There are at least b/315337725 and b/315036698 issues, reverting this cl while I fix them.

Change-Id: I644bbbe594b9dd53a99a3b6513fbcba68afe0b4a
diff --git a/cmd/sbox/sbox.go b/cmd/sbox/sbox.go
index e69a930..3364f50 100644
--- a/cmd/sbox/sbox.go
+++ b/cmd/sbox/sbox.go
@@ -22,7 +22,6 @@
 	"flag"
 	"fmt"
 	"io"
-	"io/fs"
 	"io/ioutil"
 	"os"
 	"os/exec"
@@ -479,8 +478,7 @@
 // copyOneFile copies a file and its permissions.  If forceExecutable is true it adds u+x to the
 // permissions.  If exists is allowFromNotExists it returns nil if the from path doesn't exist.
 // If write is onlyWriteIfChanged then the output file is compared to the input file and not written to
-// if it is the same, avoiding updating the timestamp. If from is a symlink, the symlink itself
-// will be copied, instead of what it points to.
+// if it is the same, avoiding updating the timestamp.
 func copyOneFile(from string, to string, forceExecutable bool, exists existsType,
 	write writeType) error {
 	err := os.MkdirAll(filepath.Dir(to), 0777)
@@ -488,7 +486,7 @@
 		return err
 	}
 
-	stat, err := os.Lstat(from)
+	stat, err := os.Stat(from)
 	if err != nil {
 		if os.IsNotExist(err) && exists == allowFromNotExists {
 			return nil
@@ -496,25 +494,6 @@
 		return err
 	}
 
-	if stat.Mode()&fs.ModeSymlink != 0 {
-		linkTarget, err := os.Readlink(from)
-		if err != nil {
-			return err
-		}
-		if write == onlyWriteIfChanged {
-			toLinkTarget, err := os.Readlink(to)
-			if err == nil && toLinkTarget == linkTarget {
-				return nil
-			}
-		}
-		err = os.Remove(to)
-		if err != nil && !os.IsNotExist(err) {
-			return err
-		}
-
-		return os.Symlink(linkTarget, to)
-	}
-
 	perm := stat.Mode()
 	if forceExecutable {
 		perm = perm | 0100 // u+x