pgsql: Make contrib regression tests safe for Danish locale.

Make contrib regression tests safe for Danish locale.

In btree_gin and citext, avoid some not-particularly-interesting
dependencies on the sorting of 'aa'.  In tsearch2, use COLLATE "C" to
remove an uninteresting dependency on locale sort order (and thereby
allow removal of a variant expected-file).

Also, in citext, avoid assuming that lower('I') = 'i'.  This isn't relevant
to Danish but it does fail in Turkish.

Branch
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REL9_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/a1e75055368e28985cec9cc2c6fc133f4e144da2

Modified Files
--------------
contrib/btree_gin/expected/bytea.out     |    6 +-
contrib/btree_gin/expected/text.out      |    6 +-
contrib/btree_gin/expected/varchar.out   |    6 +-
contrib/btree_gin/sql/bytea.sql          |    2 +-
contrib/btree_gin/sql/text.sql           |    2 +-
contrib/btree_gin/sql/varchar.sql        |    2 +-
contrib/citext/expected/citext.out       |  261 ++-
contrib/citext/expected/citext_1.out     |  261 ++-
contrib/citext/sql/citext.sql            |   43 +-
contrib/tsearch2/expected/tsearch2.out   |   12 +-
contrib/tsearch2/expected/tsearch2_1.out | 2969 ------------------------------
contrib/tsearch2/sql/tsearch2.sql        |   12 +-
12 files changed, 271 insertions(+), 3311 deletions(-)