MDEV-30032: EXPLAIN FORMAT=JSON output: print costs

Basic printout for join and table execution costs.

mysql-test/main/range.test

@@ -1920,6 +1920,7 @@ insert into t1 values
 let $q1= 
 select * from t1 where (a,b) IN ((2, 3),(3,3),(8,8),(7,7));
 eval explain $q1;
+--source include/explain-no-costs.inc
 eval explain format=json $q1;
 eval $q1;
 eval prepare stmt from "$q1";
@@ -1931,6 +1932,7 @@ deallocate prepare stmt;
 let $q2=
 select * from t1 where (a,b+a) IN ((4,9),(8,8),(7,7));
 eval explain $q2;
+--source include/explain-no-costs.inc
 eval explain format=json $q2;
 eval $q2;
 
@@ -1938,6 +1940,7 @@ eval $q2;
 let $q3=
 select * from t1 where (a,b) IN ((4,a-1),(8,a+8),(7,a+7));
 eval explain $q3;
+--source include/explain-no-costs.inc
 eval explain format=json $q3;
 eval $q3;
 
@@ -1961,6 +1964,7 @@ let $q4=
 select * from t1,t2
   where a = d and (a,e) in ((3,3),(7,7),(2,2));
 eval explain $q4;
+--source include/explain-no-costs.inc
 eval explain format=json $q4;
 eval $q4;
 
@@ -1986,6 +1990,7 @@ let $q5=
 select * from t1,t2
   where a = d and (a,e) in ((3,3),(7,7),(8,8)) and length(f) = 1;
 eval explain $q5;
+--source include/explain-no-costs.inc
 eval explain format=json $q5;
 --sorted_result
 eval $q5;
@@ -2004,6 +2009,7 @@ let $q6=
 select * from t1,t2 
   where a = d and (a,e) in ((4,4),(7,7),(8,8)) and length(f) = 1;
 eval explain $q6;
+--source include/explain-no-costs.inc
 eval explain format=json $q6;
 --sorted_result
 eval $q6;
@@ -2016,6 +2022,7 @@ let $q7=
 select * from t1,t2 
   where a = d and (a,e) in ((4,4),(7,7),(8,8)) and length(f) = 1;
 eval explain $q7;
+--source include/explain-no-costs.inc
 eval explain format=json $q7;
 eval $q7;
 
@@ -2025,6 +2032,7 @@ let $q8=
 select * from t1,t2
   where a = d and (a,e) in ((4,d+1),(7,d+1),(8,d+1)) and length(f) = 1;
 eval explain $q8;
+--source include/explain-no-costs.inc
 eval explain format=json $q8;
 --sorted_result
 eval $q8;
@@ -2035,6 +2043,7 @@ let $q9=
 select * from t1,t2
   where a = d and (a,e) in ((e,d+1),(7,7),(8,8)) and length(f) = 1;
 eval explain $q9;
+--source include/explain-no-costs.inc
 eval explain format=json $q9;
 --sorted_result
 eval $q9;
@@ -2046,6 +2055,7 @@ select * from t1,t2
   where a = d and (a,2) in ((2,2),(7,7),(8,8)) and
         length(c) = 1 and length(f) = 1;
 eval explain $q10;
+--source include/explain-no-costs.inc
 eval explain format=json $q10;
 eval $q10;
 eval prepare stmt from "$q10";
@@ -2066,6 +2076,7 @@ select * from t1,t2,t3
         (a,v+1) in ((2,2),(7,7),(8,8)) and
         length(c) = 1 and length(f) = 1;
 eval explain $q11;
+--source include/explain-no-costs.inc
 eval explain format=json $q11;
 eval $q11;