gn2bp: Convert `source_set` with rtti to static_libraries

* `source_set` were converted to cc_defaults and this would pose a huge problem if those cc_defaults had rtti on since it affected all of the dependencies of the source target.
* The solution here would be to compile the `source_set` independently as a static/shared library with rtti on then link it.

Test: m cronet_aml_components_cronet_android_cronet
Change-Id: I28bbe0947d0dc87c2d602514a2759a3171b68aa2
3 files changed