Set up rules to build shared libraries for TARGET_2ND_ARCH

The rules for the 2nd arch are set up in the second inclusion
of shared_library_internal.mk.
Intermediate fils of libfoo of the 2nd arch will be built into
$(PRODUCT_OUT)/obj_$(TARGET_2ND_ARCH)/SHARED_LIBRARIES/libfoo_intermediates/
and the built libfoo.so will be in
$(PRODUCT_OUT)/obj_$(TARGET_2ND_ARCH)/lib.

Bug: 11654773
Change-Id: I58bbe5a05a65f63bce6279131552f3792000716e