Make header-abi-linker merge type graphs.

Bug: 71486971

Test: tests/gen_all.py produces reference dumps. These reference dumps
      have type ids resolved for all exported types.

Test: mm -j64 in frameworks/av/media/libstagefright/codecs/ now produces
      libstagefright_soft_vpxenc.so.lsdump with two different instances
      of struct 'frame_contexts'. They have different sizes and layouts.
      This was the original diff that exposed the lack of support for
      ODR handling.

Test: Use built tools instead of prebuilt, build android source tree.
      Builds succesfully while producing lsdumps for vndk libraries.

Change-Id: I99cfe96512cf8d9b78b3fb1a5735ea9537a3e197