pgsql: Revise sinval code to remove no-longer-used tuple TID from inval

Revise sinval code to remove no-longer-used tuple TID from inval messages.

This requires adjusting the API for syscache callback functions: they now
get a hash value, not a TID, to identify the target tuple.  Most of them
weren't paying any attention to that argument anyway, but plancache did
require a small amount of fixing.

Also, improve performance a trifle by avoiding sending duplicate inval
messages when a heap_update isn't changing the catcache lookup columns.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/b5282aa893e565b7844f8237462cb843438cdd5e

Modified Files
--------------
src/backend/access/heap/heapam.c      |   30 +++---
src/backend/catalog/namespace.c       |    4 +-
src/backend/nodes/copyfuncs.c         |    3 +-
src/backend/nodes/outfuncs.c          |    4 +-
src/backend/optimizer/plan/setrefs.c  |   23 ++--
src/backend/optimizer/util/predtest.c |    4 +-
src/backend/parser/parse_oper.c       |    4 +-
src/backend/utils/adt/acl.c           |    4 +-
src/backend/utils/cache/attoptcache.c |    2 +-
src/backend/utils/cache/catcache.c    |   48 +++++---
src/backend/utils/cache/inval.c       |  221 ++++++++++++++++-----------------
src/backend/utils/cache/plancache.c   |   20 ++--
src/backend/utils/cache/spccache.c    |    2 +-
src/backend/utils/cache/ts_cache.c    |    2 +-
src/backend/utils/misc/superuser.c    |    6 +-
src/include/nodes/plannodes.h         |    5 +-
src/include/storage/sinval.h          |   25 ++---
src/include/utils/catcache.h          |    6 +-
src/include/utils/inval.h             |    8 +-
19 files changed, 210 insertions(+), 211 deletions(-)