gn2bp: Add is_debug and is_official_build to args.gn

args.gn generated by `cr_cronet.py gn --release` has is_debug=false and
is_official_build=true.
But current args.gn used to generate desc jsons were missing them.

Test: ./gen_desc_json.sh
Bug: 265913942
Change-Id: Ide83e770ade8574fe3d3ffe04f5481b8fde4140a
1 file changed