BUG#58246: INSTALL PLUGIN not secure & crashable

Fixing test case that fails on Windows because .dll is used.

mysql-test/t/plugin_not_embedded.test

@@ -26,6 +26,7 @@ DROP USER bug51770@localhost;
 # all platforms should cover this case.
 
 let $path = `select CONCAT_WS('/', '..', $HA_EXAMPLE_SO)`;
+--replace_regex /\.dll/.so/
 --error ER_UDF_NO_PATHS
 eval INSTALL PLUGIN example SONAME '$path';