Make the symbol wrapping work with dynamic linking

Make the symbol wrapping work with dynamic linking

When the unit test is linked with dynamic libraries, the wrapping
doesn't occur, probably because it's different translation unit.

To workaround the issue, we provide thin wrappers with *real* symbol
names that just call the mocked functions.

(cherry picked from commit 839ed7894bffb4694406d1a8d8ed8f4f840b97ef)