Revert "Switch to toybox tar."

This reverts commit 3b584b7861fe61ff802869dc30f0d6bbe3999ff3.

Reason for revert: missing --mode.

Change-Id: I0cde94c38905e26c79c31a03fd0177d7d57daa32
diff --git a/ui/build/paths/config.go b/ui/build/paths/config.go
index 7628fef..c9946e2 100644
--- a/ui/build/paths/config.go
+++ b/ui/build/paths/config.go
@@ -102,6 +102,7 @@
 	"realpath": Allowed,
 	"rsync":    Allowed,
 	"sh":       Allowed,
+	"tar":      Allowed,
 	"tr":       Allowed,
 	"unzip":    Allowed,
 	"zip":      Allowed,
@@ -163,7 +164,6 @@
 	"sort":      LinuxOnlyPrebuilt,
 	"stat":      LinuxOnlyPrebuilt,
 	"tail":      LinuxOnlyPrebuilt,
-	"tar":       LinuxOnlyPrebuilt,
 	"tee":       LinuxOnlyPrebuilt,
 	"timeout":   LinuxOnlyPrebuilt,
 	"touch":     LinuxOnlyPrebuilt,