Copy abidiffs into /abidiffs on abi breakages.

Bug: 64267858

Test: create reference abi dump for libjpeg locally. Change return type
      of libjpeg_std_err and build with :
      BOARD_VNDK_VERSION=current mm -j64 showcommands dist
      Build fails and abidiff report gets copied into out/dist/abidiffs.

Change-Id: I7c8ecfac95361e731009e5913bd3a7bb323a9597