Installd: Fix installd_dexopt_test

The introduction of system_server_startup means we need to explicitly
move to system_server's final domain.

Bug: 129140502
Test: atest installd_dexopt_test
Change-Id: I776ed44406ad75dc27383719b9a2709c00eaced0
diff --git a/cmds/installd/tests/installd_dexopt_test.cpp b/cmds/installd/tests/installd_dexopt_test.cpp
index 36d5a60..fa2b0d9 100644
--- a/cmds/installd/tests/installd_dexopt_test.cpp
+++ b/cmds/installd/tests/installd_dexopt_test.cpp
@@ -936,8 +936,7 @@
   protected:
     void TransitionToSystemServer() {
         ASSERT_TRUE(DropCapabilities(kSystemUid, kSystemGid));
-        int32_t res = selinux_android_setcontext(
-                kSystemUid, true, se_info_.c_str(), "system_server");
+        int32_t res = selinux_android_setcon("u:r:system_server:s0");
         ASSERT_EQ(0, res) << "Failed to setcon " << strerror(errno);
     }