add e2e test

e2e_test/ddl/drop/drop_creating_mv.slt

@@ -0,0 +1,41 @@
+statement ok
+create table t(v1 int);
+
+statement ok
+insert into t select * from generate_series(1, 10000);
+
+statement ok
+flush;
+
+statement ok
+set streaming_rate_limit=1;
+
+# Test drop foreground mv
+skipif madsim
+system ok
+risedev psql -c 'create materialized view m1 as select * from t;' &
+
+skipif madsim
+sleep 5s
+
+skipif madsim
+statement ok
+drop materialized view m1;
+
+# Test drop background mv
+statement ok
+set background_ddl=true;
+
+skipif madsim
+statement ok
+create materialized view m1 as select * from t;
+
+skipif madsim
+sleep 5s
+
+skipif madsim
+statement ok
+drop materialized view m1;
+
+statement ok
+drop table t;