patch 8.2.1049: Vim9: leaking memory when using continuation line

Problem:    Vim9: leaking memory when using continuation line.
Solution:   Keep a pointer to the continuation line in evalarg_T.  Centralize
            checking for a next command.
diff --git a/src/if_ole.cpp b/src/if_ole.cpp
index 34ce232..e415a19 100644
--- a/src/if_ole.cpp
+++ b/src/if_ole.cpp
@@ -388,7 +388,7 @@
 
     /* Evaluate the expression */
     ++emsg_skip;
-    str = (char *)eval_to_string((char_u *)buffer, NULL, TRUE);
+    str = (char *)eval_to_string((char_u *)buffer, TRUE);
     --emsg_skip;
     vim_free(buffer);
     if (str == NULL)