os/bluestore: fix unexpected ENOSPC in Avl/Hybrid allocators.

os/bluestore: fix unexpected ENOSPC in Avl/Hybrid allocators.

Avl allocator mode was returning unexpected ENOSPC in first-fit mode if all size-
matching available extents were unaligned but applying the alignment made all of
them shorter than required. Since no lookup retry with smaller size -
ENOSPC is returned.
Additionally we should proceed with a lookup in best-fit mode even when
original size has been truncated to match the avail size.
(force_range_size_alloc==true)

Fixes: https://tracker.ceph.com/issues/50656
Signed-off-by: Igor Fedotov <ifedotov@suse.com>
(cherry picked from commit 0eed13a4969d02eeb23681519f2a23130e51ac59)

 Conflicts:
	src/test/objectstore/Allocator_test.cc - legacy INSTANTIATE_TEST_CASE_P clause is still used in Nautilus