bugfix: stored column depends on virtual depends on updated

TABLE::mark_virtual_col() was polluting table->vcol_set
and that confused the following mark_virtual_col()

1 files changed, 10 insertions, 0 deletions

diff --git a/mysql-test/suite/vcol/r/update.result b/mysql-test/suite/vcol/r/update.result
new file mode 100644
index 00000000000..d56f85c1f1c
--- /dev/null
+++ b/mysql-test/suite/vcol/r/update.result
@@ -0,0 +1,10 @@
+create table t1 (a int, b int as (a+1), c int as (b+1) stored);
+insert t1 set a=1;
+select * from t1;
+a	b	c
+1	2	3
+update t1 set a=2;
+select * from t1;
+a	b	c
+2	3	4
+drop table t1;