BUG#39934: Slave stops for engine that only support row-based logging

This is a post-push fix addressing review requests and
problems with extra warnings.

Problem 1: The sub-statement where an unsafe warning was detected was
printed as part of the warning. This was ok for statements that
were unsafe due to, e.g., calls to UUID(), but did not make
sense for statements that were unsafe because there was more than
one autoincrement column (unsafeness in this case comes from the
combination of several sub-statements).
Fix 1: Instead of printing the sub-statement, print an explanation
of why the statement is unsafe.

Problem 2:
When a recursive construct (i.e., stored proceure, stored
function, trigger, view, prepared statement) contained several
sub-statements, and at least one of them was unsafe, there would be
one unsafeness warning per sub-statement - even for safe
sub-statements.
Fix 2:
Ensure that each type of warning is printed at most once, by
remembering throughout the execution of the statement which types
of warnings have been printed.

sql/sql_view.cc

@@ -1306,8 +1306,8 @@ bool mysql_make_view(THD *thd, File_parser *parser, TABLE_LIST *table,
       If the view's body needs row-based binlogging (e.g. the VIEW is created
       from SELECT UUID()), the top statement also needs it.
     */
-    if (lex->is_stmt_unsafe())
-      old_lex->set_stmt_unsafe();
+    old_lex->set_stmt_unsafe_flags(lex->get_stmt_unsafe_flags());
+
     view_is_mergeable= (table->algorithm != VIEW_ALGORITHM_TMPTABLE &&
                         lex->can_be_merged());
     LINT_INIT(view_main_select_tables);