gn2bp: Convert cc_objects to cc_static_library

* cc_objects are more like source-sets. However, they are not commonly used in AOSP which makes it risky to rely on them.
* Clang native code coverage is not working for cc_objects. Which is needed for the dashboard.

Size Delta to .SO
x64: -0.1MB
x86: 0MB
arm: 0MB
arm64: 0MB

Test: m
Bug: 270027426
Change-Id: I1d74e0293dac91334bded73b0e89465b7af7480c