Confine vacuum skip logic to lazy_scan_skip

Applying: Improve API for retrieving data from read streams.
Using index info to reconstruct a base tree...
M	contrib/pg_prewarm/pg_prewarm.c
M	contrib/pg_visibility/pg_visibility.c
M	src/backend/access/heap/heapam.c
M	src/backend/access/heap/heapam_handler.c
M	src/backend/access/heap/vacuumlazy.c
M	src/backend/storage/aio/read_stream.c
M	src/backend/storage/buffer/bufmgr.c
M	src/include/storage/read_stream.h
Falling back to patching base and 3-way merge...
Auto-merging src/include/storage/read_stream.h
Auto-merging src/backend/storage/buffer/bufmgr.c
Auto-merging src/backend/storage/aio/read_stream.c
CONFLICT (content): Merge conflict in src/backend/storage/aio/read_stream.c
Auto-merging src/backend/access/heap/vacuumlazy.c
CONFLICT (content): Merge conflict in src/backend/access/heap/vacuumlazy.c
Auto-merging src/backend/access/heap/heapam_handler.c
Auto-merging src/backend/access/heap/heapam.c
Auto-merging contrib/pg_visibility/pg_visibility.c
Auto-merging contrib/pg_prewarm/pg_prewarm.c
Patch failed at 0001 Improve API for retrieving data from read streams.

error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"