MDEV-27955 main.func_json_notembedded test fails on out-of-memory

Uses 500M+ of memory by repeating an 8 byte sequence 62.5M times.

Reduce the number of repeats on string reduced by 100 times.

Tested by applying against the reverted MDEV-24909 code. 1000 times
reduction was too much, but 100 still managed to trigger the bug.

mysql-test/main/func_json_notembedded.result

@@ -4,11 +4,11 @@ connect u,localhost,root;
 # MDEV-24909 JSON functions don't respect KILL QUERY / max_statement_time limit
 #
 set group_concat_max_len= 4294967295;
-set @obj=concat_ws('','{', repeat('"a":"b",', 125000000/2), '"c":"d"}');
-set @arr=concat_ws('','[', repeat('1234567,', 125000000/2), '2345678]');
+set @obj=concat_ws('','{', repeat('"a":"b",', 1250000/2), '"c":"d"}');
+set @arr=concat_ws('','[', repeat('1234567,', 1250000/2), '2345678]');
 select length(@obj), length(@arr);
 length(@obj)	length(@arr)
-500000009	500000009
+5000009	5000009
 set max_statement_time=0.0001;
 select json_array_append(@arr, '$[0]', 1);
 ERROR 70100: Query execution was interrupted (max_statement_time exceeded)

mysql-test/main/func_json_notembedded.test

@@ -9,8 +9,8 @@ connect u,localhost,root;
 --echo #
 set group_concat_max_len= 4294967295;
 
-set @obj=concat_ws('','{', repeat('"a":"b",', 125000000/2), '"c":"d"}');
-set @arr=concat_ws('','[', repeat('1234567,', 125000000/2), '2345678]');
+set @obj=concat_ws('','{', repeat('"a":"b",', 1250000/2), '"c":"d"}');
+set @arr=concat_ws('','[', repeat('1234567,', 1250000/2), '2345678]');
 select length(@obj), length(@arr);
 
 set max_statement_time=0.0001;