pgsql: Rewrite GiST support code for rangetypes.

Rewrite GiST support code for rangetypes.

This patch installs significantly smarter penalty and picksplit functions
for ranges, making GiST indexes for them smaller and faster to search.

There is no on-disk format change, so no catversion bump, but you'd need
to REINDEX to get the benefits for any existing index.

Alexander Korotkov, reviewed by Jeff Davis

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/80da9e68fdd70b796b3a7de3821589513596c0f7

Modified Files
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src/backend/utils/adt/rangetypes_gist.c | 1293 ++++++++++++++++++++++++++-----
1 files changed, 1102 insertions(+), 191 deletions(-)