Align base_system and core_minimal with internal.

Move a few things up from core_minimal.mk to base_system, and make
a few other editing tweaks in base_system, to align it more closely
with the internal version.

Test: make
Change-Id: I3d0fd22ea1cf94b0d28610cc15e23aca3ddd21c4
Merged-In: Iddffd6982df039f5daa8be345de338ba11c63c10