pgsql: Factor out encoding specific tests for json

Factor out encoding specific tests for json

This lets us remove the large alternative results files for the main
json and jsonb tests, which makes modifying those tests simpler for
committers and patch submitters.

Backpatch to 9.4 for jsonb and 9.3 for json.

Branch
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REL9_3_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/f844f0ef18707f370f0060b7925c6371298e9242

Modified Files
--------------
src/test/regress/expected/json.out            |   73 +-
src/test/regress/expected/json_1.out          |  976 -------------------------
src/test/regress/expected/json_encoding.out   |   74 ++
src/test/regress/expected/json_encoding_1.out |   70 ++
src/test/regress/parallel_schedule            |    2 +-
src/test/regress/serial_schedule              |    1 +
src/test/regress/sql/json.sql                 |   19 +-
src/test/regress/sql/json_encoding.sql        |   23 +
8 files changed, 171 insertions(+), 1067 deletions(-)