tests/misc/check_init_priorities: Use hwmv2 native targets ident

For the 64 bit targets, change identifiers to the new hwmv2 ones
And remove redundant overlays (which were equal for the 32
and 64 bit versions)

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>

tests/misc/check_init_priorities/boards/native_sim_64.overlay

@@ -1,6 +0,0 @@
-/*
- * Copyright 2023 Google LLC
- *
- * SPDX-License-Identifier: Apache-2.0
- */
-#include "native_sim.overlay"

tests/misc/check_init_priorities/testcase.yaml

@@ -5,7 +5,7 @@ tests:
     build_only: true
     platform_allow:
       - native_sim
-      - native_sim_64
+      - native_sim/native/64
       - native_posix
     integration_platforms:
       - native_sim