flush bulk-insert tree on dup key

mysql-test/t/bulk_replace.test

@@ -0,0 +1,14 @@
+#
+# this is a test of bulk-insert code
+# as used by REPLACE
+#
+# by Monty
+#
+
+drop table if exists t1;
+CREATE TABLE t1 (a int, unique (a), b int not null, unique(b), c int not null, index(c));
+replace into t1 values (1,1,1),(2,2,2),(3,1,3);
+select * from t1;
+check table t1;
+drop table t1;
+