Improve monitoring of shared memory allocations

Applying: Improve accounting for memory used by shared hash tables
Using index info to reconstruct a base tree...
M	src/backend/storage/ipc/shmem.c
M	src/backend/utils/hash/dynahash.c
M	src/include/utils/hsearch.h
Falling back to patching base and 3-way merge...
Auto-merging src/include/utils/hsearch.h
CONFLICT (content): Merge conflict in src/include/utils/hsearch.h
Auto-merging src/backend/utils/hash/dynahash.c
CONFLICT (content): Merge conflict in src/backend/utils/hash/dynahash.c
Auto-merging src/backend/storage/ipc/shmem.c
CONFLICT (content): Merge conflict in src/backend/storage/ipc/shmem.c
Patch failed at 0001 Improve accounting for memory used by shared hash tables

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"