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.

Author: adunstan

src/test/regress/expected/json.out

@@ -42,36 +42,7 @@ LINE 1: SELECT '"\v"'::json;
                ^
 DETAIL:  Escape sequence "\v" is invalid.
 CONTEXT:  JSON data, line 1: "\v...
-SELECT '"\u"'::json;			-- ERROR, incomplete escape
-ERROR:  invalid input syntax for type json
-LINE 1: SELECT '"\u"'::json;
-               ^
-DETAIL:  "\u" must be followed by four hexadecimal digits.
-CONTEXT:  JSON data, line 1: "\u"
-SELECT '"\u00"'::json;			-- ERROR, incomplete escape
-ERROR:  invalid input syntax for type json
-LINE 1: SELECT '"\u00"'::json;
-               ^
-DETAIL:  "\u" must be followed by four hexadecimal digits.
-CONTEXT:  JSON data, line 1: "\u00"
-SELECT '"\u000g"'::json;		-- ERROR, g is not a hex digit
-ERROR:  invalid input syntax for type json
-LINE 1: SELECT '"\u000g"'::json;
-               ^
-DETAIL:  "\u" must be followed by four hexadecimal digits.
-CONTEXT:  JSON data, line 1: "\u000g...
-SELECT '"\u0000"'::json;		-- OK, legal escape
-   json   
-----------
- "\u0000"
-(1 row)
-
-SELECT '"\uaBcD"'::json;		-- OK, uppercase and lower case both OK
-   json   
-----------
- "\uaBcD"
-(1 row)
-
+-- see json_encoding test for input with unicode escapes
 -- Numbers.
 SELECT '1'::json;				-- OK
  json 
@@ -1419,88 +1390,6 @@ select * from json_populate_recordset(row('def',99,null)::jpop,'[{"a":[100,200,3
  {"z":true}    |  3 | Fri Jan 20 10:42:53 2012
 (2 rows)
 
--- handling of unicode surrogate pairs
-select json '{ "a":  "\ud83d\ude04\ud83d\udc36" }' -> 'a' as correct_in_utf8;
-      correct_in_utf8       
-----------------------------
- "\ud83d\ude04\ud83d\udc36"
-(1 row)
-
-select json '{ "a":  "\ud83d\ud83d" }' -> 'a'; -- 2 high surrogates in a row
-ERROR:  invalid input syntax for type json
-DETAIL:  Unicode high surrogate must not follow a high surrogate.
-CONTEXT:  JSON data, line 1: { "a":...
-select json '{ "a":  "\ude04\ud83d" }' -> 'a'; -- surrogates in wrong order
-ERROR:  invalid input syntax for type json
-DETAIL:  Unicode low surrogate must follow a high surrogate.
-CONTEXT:  JSON data, line 1: { "a":...
-select json '{ "a":  "\ud83dX" }' -> 'a'; -- orphan high surrogate
-ERROR:  invalid input syntax for type json
-DETAIL:  Unicode low surrogate must follow a high surrogate.
-CONTEXT:  JSON data, line 1: { "a":...
-select json '{ "a":  "\ude04X" }' -> 'a'; -- orphan low surrogate
-ERROR:  invalid input syntax for type json
-DETAIL:  Unicode low surrogate must follow a high surrogate.
-CONTEXT:  JSON data, line 1: { "a":...
---handling of simple unicode escapes
-select json '{ "a":  "the Copyright \u00a9 sign" }' as correct_in_utf8;
-            correct_in_utf8            
----------------------------------------
- { "a":  "the Copyright \u00a9 sign" }
-(1 row)
-
-select json '{ "a":  "dollar \u0024 character" }' as correct_everywhere;
-         correct_everywhere          
--------------------------------------
- { "a":  "dollar \u0024 character" }
-(1 row)
-
-select json '{ "a":  "dollar \\u0024 character" }' as not_an_escape;
-            not_an_escape             
---------------------------------------
- { "a":  "dollar \\u0024 character" }
-(1 row)
-
-select json '{ "a":  "null \u0000 escape" }' as not_unescaped;
-         not_unescaped          
---------------------------------
- { "a":  "null \u0000 escape" }
-(1 row)
-
-select json '{ "a":  "null \\u0000 escape" }' as not_an_escape;
-          not_an_escape          
----------------------------------
- { "a":  "null \\u0000 escape" }
-(1 row)
-
-select json '{ "a":  "the Copyright \u00a9 sign" }' ->> 'a' as correct_in_utf8;
-   correct_in_utf8    
-----------------------
- the Copyright © sign
-(1 row)
-
-select json '{ "a":  "dollar \u0024 character" }' ->> 'a' as correct_everywhere;
- correct_everywhere 
---------------------
- dollar $ character
-(1 row)
-
-select json '{ "a":  "dollar \\u0024 character" }' ->> 'a' as not_an_escape;
-      not_an_escape      
--------------------------
- dollar \u0024 character
-(1 row)
-
-select json '{ "a":  "null \u0000 escape" }' ->> 'a' as fails;
-ERROR:  unsupported Unicode escape sequence
-DETAIL:  \u0000 cannot be converted to text.
-CONTEXT:  JSON data, line 1: { "a":...
-select json '{ "a":  "null \\u0000 escape" }' ->> 'a' as not_an_escape;
-   not_an_escape    
---------------------
- null \u0000 escape
-(1 row)
-
 --json_typeof() function
 select value, json_typeof(value)
   from (values (json '123.4'),