MDEV-15561 json_extract returns NULL with numbers in scientific notation.

Scientific notation handling fixed.

mysql-test/r/func_json.result

@@ -736,3 +736,6 @@ insert into t1 values (2),(1);
 select 1 from t1 where json_extract(a,'$','$[81]');
 1
 drop table t1;
+select json_extract('{"test":8.437e-5}','$.test');
+json_extract('{"test":8.437e-5}','$.test')
+8.437e-5

mysql-test/t/func_json.test

@@ -392,3 +392,9 @@ insert into t1 values (2),(1);
 select 1 from t1 where json_extract(a,'$','$[81]');
 drop table t1;
 
+#
+# MDEV-15561 json_extract returns NULL with numbers in scientific notation.
+#
+
+select json_extract('{"test":8.437e-5}','$.test');
+

strings/json_lib.c

@@ -475,8 +475,8 @@ static int json_num_states[NS_NUM_STATES][N_NUM_CLASSES]=
 /*ZE1*/  { JE_SYN,  JE_SYN, JE_SYN,   JE_SYN, NS_FRAC, JE_SYN, NS_OK,  JE_BAD_CHR },
 /*INT*/  { JE_SYN,  JE_SYN, NS_INT,   NS_INT, NS_FRAC, NS_EX,  NS_OK,  JE_BAD_CHR },
 /*FRAC*/ { JE_SYN,  JE_SYN, NS_FRAC,  NS_FRAC,JE_SYN,  NS_EX,  NS_OK,  JE_BAD_CHR },
-/*EX*/   { NS_EX1,  NS_EX1, NS_EX1,   NS_EX1, JE_SYN,  JE_SYN, JE_SYN, JE_BAD_CHR }, 
-/*EX1*/  { JE_SYN,  JE_SYN, NS_EX1,   NS_EX1, JE_SYN,  JE_SYN, JE_SYN, JE_BAD_CHR }
+/*EX*/   { NS_EX,   NS_EX,  NS_EX1,   NS_EX1, JE_SYN,  JE_SYN, JE_SYN, JE_BAD_CHR }, 
+/*EX1*/  { JE_SYN,  JE_SYN, NS_EX1,   NS_EX1, JE_SYN,  JE_SYN, NS_OK,  JE_BAD_CHR }
 };