ANDROID: vendor_hooks: Add hooks to for alloc_contig_range

Provide a vendor hook to allow drain_all_pages to be skipped
during alloc_contig_range in some cases to avoid delays caused by
it in cases when the benefits of draining pcp lists are known
to be small.

Bug: 224732340
Signed-off-by: Peifeng Li <lipeifeng@oppo.com>
Change-Id: I0a82f668cf985ad5344d666c0c6372a7e61c3798