A few patches to clarify snapshot management, part 2

Applying: Add sanity checks against using non-MVCC snapshots incorrectly
Using index info to reconstruct a base tree...
M	contrib/amcheck/verify_heapam.c
M	contrib/amcheck/verify_nbtree.c
M	src/backend/access/transam/parallel.c
M	src/backend/catalog/pg_inherits.c
M	src/backend/commands/async.c
M	src/backend/partitioning/partdesc.c
M	src/backend/utils/adt/xid8funcs.c
M	src/backend/utils/time/snapmgr.c
Falling back to patching base and 3-way merge...
Auto-merging src/backend/utils/time/snapmgr.c
Auto-merging src/backend/utils/adt/xid8funcs.c
Auto-merging src/backend/partitioning/partdesc.c
Auto-merging src/backend/commands/async.c
CONFLICT (content): Merge conflict in src/backend/commands/async.c
Auto-merging src/backend/catalog/pg_inherits.c
Auto-merging src/backend/access/transam/parallel.c
Auto-merging contrib/amcheck/verify_nbtree.c
Auto-merging contrib/amcheck/verify_heapam.c
Patch failed at 0001 Add sanity checks against using non-MVCC snapshots incorrectly

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"