checkpoint: resolve symlink for external bind mount(fix ci broken)

runc resolves symlink before doing bind mount. So
we should save original path while formatting CriuReq for
dump and restore.

"checkpoint: resolve symlink for external bind mount" is merged as
da22625f6986f0ef196eaa1f8bb6adce098f0fb7(PR 2902) previously. And reverted
in commit 70fdc0573dced3464e9c31d674559f77c1de3973(PR 3043) duo to behavior changes
caused by commit 0ca91f44f1664da834bc61115a849b56d22f595f(Fixes: CVE-2021-30465)

Signed-off-by: Liu Hua <weldonliu@tencent.com>

tests/integration/checkpoint.bats

@@ -126,7 +126,18 @@ function simple_cr() {
 	done
 }
 
-@test "checkpoint and restore " {
+@test "checkpoint and restore" {
+	simple_cr
+}
+
+@test "checkpoint and restore (bind mount, destination is symlink)" {
+	mkdir -p rootfs/real/conf
+	ln -s /real/conf rootfs/conf
+	update_config '	  .mounts += [{
+					source: ".",
+					destination: "/conf",
+					options: ["bind"]
+				}]'
 	simple_cr
 }