Fix js mapping error regression

[rsora]

This PR solves OpenAPI rgeneration regression for JS client (see here)

$npm run test                                                                                                                                                                                                   
                                                                                                                                                                                                                   
> @arduino/[email protected] test /home/rsora/code/projects/arduino/iot-client-js                                                                                                                           
> mocha --require @babel/register --recursive                                                                                                                                                                      
                                                                                                                                                                                                                   
internal/modules/cjs/loader.js:1017                                                                                                                                                                                
  throw err;                                                                                                                                                                                                       
  ^                                                                                                                                                                                                                
                                                                                                                                                                                                                   
Error: Cannot find module './AnyType'                                                                                                                                                                              
Require stack:  

In addition, generated tests are removed for py and js client as they are pretty useless, a PR will be opened in related client repos to implement simple integ tests