Merge changes I4ffc7c9f,I6be5ed04,I758b9b26,Ib7cd1969,I2f750e15, ...

* changes:
  gn2bp: Update desc_*.json due to overwriting
  gn2bp: Only compile x64 for host machines
  gn2bp: Change stem for test targets
  gn2bp: Duplicate cronet_aml_java for testing
  gn2bp: Duplicate genrules that affect the JNI/Jarjar
  gn2bp: Duplicate modules reachable from test targets
  gn2bp: Prevent collection of source files for testing modules
  gn2bp: Add `cronet_unittests_android` to the generated Android.bp