patch 9.2.0738: ml_recover() may write beyond block buffer

patch 9.2.0738: ml_recover() may write beyond block buffer

Problem:  A crafted swap file can cause an out-of-bounds write during
          recovery when the same block is referenced twice with
          different pe_page_count values (cipher-creator)
Solution: Check hp->bh_page_count against page_count after mf_get() and
          clamp page_count to the actual block size.

closes: #20645

Signed-off-by: Christian Brabandt <cb@256bit.org>