Fix insufficiently-portable regression test case.

Some of the buildfarm members are evidently miserly enough of stack space
to pass the originally-committed form of this test.  Increase the
requirement 10X to hopefully ensure that it fails as-expected everywhere.

Security: CVE-2015-5289

src/test/regress/expected/json.out

@@ -233,10 +233,10 @@ DETAIL:  Expected string, but found "3".
 CONTEXT:  JSON data, line 1: {"abc":1,3...
 -- Recursion.
 SET max_stack_depth = '100kB';
-SELECT repeat('[', 1000)::json;
+SELECT repeat('[', 10000)::json;
 ERROR:  stack depth limit exceeded
 HINT:  Increase the configuration parameter "max_stack_depth" (currently 100kB), after ensuring the platform's stack depth limit is adequate.
-SELECT repeat('{"a":', 1000)::json;
+SELECT repeat('{"a":', 10000)::json;
 ERROR:  stack depth limit exceeded
 HINT:  Increase the configuration parameter "max_stack_depth" (currently 100kB), after ensuring the platform's stack depth limit is adequate.
 RESET max_stack_depth;

src/test/regress/expected/json_1.out

@@ -233,10 +233,10 @@ DETAIL:  Expected string, but found "3".
 CONTEXT:  JSON data, line 1: {"abc":1,3...
 -- Recursion.
 SET max_stack_depth = '100kB';
-SELECT repeat('[', 1000)::json;
+SELECT repeat('[', 10000)::json;
 ERROR:  stack depth limit exceeded
 HINT:  Increase the configuration parameter "max_stack_depth" (currently 100kB), after ensuring the platform's stack depth limit is adequate.
-SELECT repeat('{"a":', 1000)::json;
+SELECT repeat('{"a":', 10000)::json;
 ERROR:  stack depth limit exceeded
 HINT:  Increase the configuration parameter "max_stack_depth" (currently 100kB), after ensuring the platform's stack depth limit is adequate.
 RESET max_stack_depth;

src/test/regress/sql/json.sql

@@ -47,8 +47,8 @@ SELECT '{"abc":1,3}'::json;		-- ERROR, no value
 
 -- Recursion.
 SET max_stack_depth = '100kB';
-SELECT repeat('[', 1000)::json;
-SELECT repeat('{"a":', 1000)::json;
+SELECT repeat('[', 10000)::json;
+SELECT repeat('{"a":', 10000)::json;
 RESET max_stack_depth;
 
 -- Miscellaneous stuff.