Order of ModuleNode#getImports() is expected but not guaranteed

One of last statements in AstBuilder.visitImportDeclaration() are

moduleNode.addImport(alias, classNode, annotationNodeList);

importNode = last(moduleNode.getImports());

Since ModuleNode.imports is a HashMap, last() method return unpredictable result.

I guess this can be fixed by changing the implementation of ModuleNode.imports into LinkedHashMap instead of HashMap as is currently.

I stumbled on this while trying to use CodeNarc with the latest Groovy.