Merge changes I6025abba,I7788a6bb,I4fe381a2,Ib1ee183e,Ifb8843aa, ...

* changes:
  gn2bp: create one action per arch
  gn2bp: support multiple jni registration modules
  gn2bp: get rid of local_include_dir hacks
  gn2bp: remove jni_headers from jni_generator genrule
  gn2bp: add common header dependencies to defaults
  gn2bp: unconditionally remove -DANDROID for all host targets