BUG#39746 - Debug flag breaks struct definition

(server crash)

Altering a table with fulltext index[es] which use
pluggable fulltext parser may cause server crash
in debug builds.

The problem was that ALTER TABLE code wrongly assigned
fulltext parser name.

Also fixed that altering a table with fulltext index[es]
leave stale fulltext parser locks, which prevent
fulltext parsers from being uninstalled after
ALTER TABLE.

mysql-test/include/have_simple_parser.inc

@@ -0,0 +1,16 @@
+#
+# Check if server has support for loading udf's
+# i.e it will support dlopen
+#
+--require r/have_dynamic_loading.require
+disable_query_log;
+show variables like 'have_dynamic_loading';
+enable_query_log;
+
+#
+# Check if the variable SIMPLE_PARSER is set
+#
+--require r/have_simple_parser.require
+disable_query_log;
+eval select LENGTH('$SIMPLE_PARSER') > 0 as 'have_simple_parser';
+enable_query_log;