binder_alloc_selftest tests that alloc_new_buf handles page allocation and
deallocation properly when allocate and free buffers. The test allocates 5
buffers of various sizes to cover all possible page alignment cases, and
frees the buffers using a list of exhaustive freeing order.

Test: boot the device with ANDROID_BINDER_IPC_SELFTEST config option
enabled. Allocator selftest passes.
Signed-off-by: NSherry Yang <sherryy@android.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>