patch 8.2.2916: operators are not fully tested

Problem:    Operators are not fully tested.
Solution:   Add a few more tests. (Yegappan Lakshmanan, closes #8290)
diff --git a/src/ops.c b/src/ops.c
index e4590a1..87fb2a0 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -2383,9 +2383,10 @@
 #ifdef FEAT_NETBEANS_INTG
 	    if (netbeans_active() && one_change)
 	    {
-		char_u *ptr = ml_get_buf(curbuf, pos.lnum, FALSE);
+		char_u *ptr;
 
 		netbeans_removed(curbuf, pos.lnum, pos.col, (long)length);
+		ptr = ml_get_buf(curbuf, pos.lnum, FALSE);
 		netbeans_inserted(curbuf, pos.lnum, pos.col,
 						&ptr[pos.col], length);
 	    }