Functions for reading the public libraries list are moved out of
library_namespace.cpp to public_libraries.cpp.
In addition, library-local symbols are moved from android namespace to
android::nativeloader namespace.
Bug: 130388701
Test: build & pass presubmit tests
Change-Id: If82419598304d56d29bfec4ef553443c788d0f53
native_loader.cpp is too crowded. Move the classes
NativeLoaderNamespaces and LibraryNamespaces out of native_loader.cpp to
their own source files.
This change does not alter any functionality.
Bug: 130388701
Test: m, presubmit tests
Change-Id: Ibc61ec0dc6727af7cac865b1971ebf1befac6855