This change adds crtbegin_so.o and crtend_so.o under
platforms/android-3/arch-arm/lib.
This is in preparation of another toolchain patch that will require
these files for all platform versions (for now, they are only defined
starting from android-9).
Note that these files are just copies of the existing ones, named
crtbegin_dynamic.o and crtend_android.o respectively.
The NDK build script will automatically use the new files if it finds
them, so shouldn't need to be updated.
Change-Id: I6a446266b54b871cd957dfd737054b302678b2d3
75cedfadcd