tests/misc/kconfigoptions: Switch to native_sim

Switch from native_posix to native_sim as test platform
and switch overlay to native_sim.

Signed-off-by: Alberto Escolar Piedras <[email protected]>

Author: aescolar

tests/misc/kconfigoptions/native_posix.overlay renamed to tests/misc/kconfigoptions/native_sim.overlay

@@ -1,4 +1,4 @@
 tests:
   kconfig.kconfigoptions:
     tags: kconfigoptions
-    platform_allow: native_posix
+    platform_allow: native_sim