[vts-core] Remove extra folder for vts_core_liblp_test and vts_libdm_test

Remove the extra folder of vts_core for vts_core_liblp_test and
vts_libdm_test since we have a better auto-gen option of auto_gen_config.

Bug: 141684102
Test: 1. m -j vts_core_liblp_test
      2. m -j vts_libdm_test
      3. check out/.../vts_core_liblp_test.config
         and
         out/.../vts_libdm_test.config

Change-Id: Ibcdf96104205b50b3da522364199330ad0190c70