Bug#20429156: "filtered" field in EXPLAIN JSON output has too high precision

The "filtered" field is printed with "unlimited" precision which may
cause small differences in 32-bit and 64-bit runs, due to floating
point approximation errors.

Adjust "filtered" column to have 2 digit precision after decimal point.

Author: roylyseng

mysql-test/include/explain_utils.inc

@@ -68,7 +68,7 @@ SHOW STATUS WHERE (Variable_name LIKE 'Sort%' OR
 if ($json) {
 if ($innodb) {
   if ($no_rows) {
---replace_regex /"rows_examined_per_scan": [0-9]+/"rows_examined_per_scan": "X"/ /_per_join": [0-9]+/_per_join": "X"/ /_per_join": "[0-9]+K"/_per_join": "X"/  /"filtered": [0-9.]+/"filtered": "X"/ /_cost": "[0-9.]+"/_cost": "X"/ /"data_read_per_join": "[0-9.]+"/"data_read_per_join": "X"/
+--replace_regex /"rows_examined_per_scan": [0-9]+/"rows_examined_per_scan": "X"/ /_per_join": [0-9]+/_per_join": "X"/ /_per_join": "[0-9]+K"/_per_join": "X"/  /"filtered": "[0-9.]+"/"filtered": "X"/ /_cost": "[0-9.]+"/_cost": "X"/ /"data_read_per_join": "[0-9.]+"/"data_read_per_join": "X"/
 }
 }
 --eval EXPLAIN FORMAT=JSON $query;
@@ -103,7 +103,7 @@ SHOW STATUS WHERE (Variable_name LIKE 'Sort%' OR
 if ($json) {
 if ($innodb) {
   if ($no_rows) {
---replace_regex /"rows_examined_per_scan": [0-9]+/"rows_examined_per_scan": "X"/ /_per_join": [0-9]+/_per_join": "X"/ /_per_join": "[0-9]+K"/_per_join": "X"/  /"filtered": [0-9.]+/"filtered": "X"/ /_cost": "[0-9.]+"/_cost": "X"/ /"data_read_per_join": "[0-9.]+"/"data_read_per_join": "X"/
+--replace_regex /"rows_examined_per_scan": [0-9]+/"rows_examined_per_scan": "X"/ /_per_join": [0-9]+/_per_join": "X"/ /_per_join": "[0-9]+K"/_per_join": "X"/  /"filtered": "[0-9.]+"/"filtered": "X"/ /_cost": "[0-9.]+"/_cost": "X"/ /"data_read_per_join": "[0-9.]+"/"data_read_per_join": "X"/
   }
 }
 --eval EXPLAIN FORMAT=JSON $select;

mysql-test/r/explain.result

@@ -42,7 +42,7 @@ EXPLAIN
       ],
       "rows_examined_per_scan": 1,
       "rows_produced_per_join": 1,
-      "filtered": 100,
+      "filtered": "100.00",
       "index_condition": "isnull(`test`.`t1`.`str`)",
       "cost_info": {
         "read_cost": "1.00",
@@ -267,7 +267,7 @@ EXPLAIN
       "access_type": "ALL",
       "rows_examined_per_scan": 4,
       "rows_produced_per_join": 4,
-      "filtered": 100,
+      "filtered": "100.00",
       "cost_info": {
         "read_cost": "10.20",
         "eval_cost": "0.80",
@@ -299,7 +299,7 @@ EXPLAIN
                   "access_type": "ALL",
                   "rows_examined_per_scan": 2,
                   "rows_produced_per_join": 2,
-                  "filtered": 100,
+                  "filtered": "100.00",
                   "cost_info": {
                     "read_cost": "2.00",
                     "eval_cost": "0.40",
@@ -317,7 +317,7 @@ EXPLAIN
                   "access_type": "ALL",
                   "rows_examined_per_scan": 2,
                   "rows_produced_per_join": 4,
-                  "filtered": 100,
+                  "filtered": "100.00",
                   "using_join_buffer": "Block Nested Loop",
                   "cost_info": {
                     "read_cost": "2.00",

mysql-test/r/explain_for_connection_crash.result

@@ -4,7 +4,7 @@ STATUS:NOT_EQUAL
 SYNC_POINT:before_reset_query_plan
 Diff: EXPLAIN NORMAL vs OTHER
 @@ -39,2 +39,3 @@
-             "filtered": 25,
+             "filtered": "25.00",
 +            "using_where": true,
              "cost_info": {
 @@ -48,4 +49,3 @@
@@ -18,7 +18,7 @@ STATUS:NOT_EQUAL
 SYNC_POINT:before_reset_query_plan
 Diff: EXPLAIN NORMAL vs OTHER
 @@ -79,2 +79,3 @@
-               "filtered": 50,
+               "filtered": "50.00",
 +              "using_where": true,
                "cost_info": {
 @@ -87,4 +88,3 @@