Make rocksdb.rocksdb_icp test stable

storage/rocksdb/mysql-test/rocksdb/r/rocksdb_icp.result

@@ -240,12 +240,12 @@ A.a+10*B.a+100*C.a,
 from t0 A, t0 B, t0 C;
 set @count=0;
 explain 
-select * from t1 where key1=1;
+select * from t1 force index(key1) where key1=1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	key1	key1	9	const	#	
 set @count_diff =(select (value - @count) from information_schema.rocksdb_perf_context 
 where table_schema=database() and table_name='t1' and stat_type='INTERNAL_KEY_SKIPPED_COUNT');
-select * from t1 where key1=1;
+select * from t1 force index(key1) where key1=1;
 pk	key1	col1
 1	1	1234
 set @count_diff =(select (value - @count) from information_schema.rocksdb_perf_context 

storage/rocksdb/mysql-test/rocksdb/t/rocksdb_icp.test

@@ -32,10 +32,10 @@ set @count_diff =(select (value - @count) from information_schema.rocksdb_perf_c
 
 --replace_column 9 #
 explain 
-select * from t1 where key1=1;
+select * from t1 force index(key1) where key1=1;
 
 eval $save_query;
-select * from t1 where key1=1;
+select * from t1 force index(key1) where key1=1;
 eval $save_query;
 --echo # The following must be =1, or in any case not 999:
 select @count_diff as "INTERNAL_KEY_SKIPPED_COUNT increment";