Always generate lowercase column aliases

This change is needed by hibernate-rx as a workaround for behavior
of the Postgres client. But anyway I think it's cleaner.

hibernate-core/src/main/java/org/hibernate/mapping/Column.java

@@ -113,7 +113,7 @@ public String getAlias(Dialect dialect) {
 		final int lastLetter = StringHelper.lastIndexOfLetter( name );
 		final String suffix = AliasConstantsHelper.get( uniqueInteger );
 
-		String alias = name;
+		String alias = name.toLowerCase( Locale.ROOT );
 		if ( lastLetter == -1 ) {
 			alias = "column";
 		}