wasm: make qtloader print stack trace on exception

We were displaying the exception type by on the error
page, however the exception contains a stack trace as
well which we can print to the console.

Pick-to: 6.4 6.5
Change-Id: Ia6c95c3f179eb68e57f9d6d2d8ad960591d0b365
Reviewed-by: Aleksandr Reviakin <aleksandr.reviakin@qt.io>
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>

src/plugins/platforms/wasm/qtloader.js

@@ -413,6 +413,8 @@ function _QtLoader(config)
             } else {
                 publicAPI.exitText = exception.toString();
                 publicAPI.crashed = true;
+                // Print stack trace to console
+                console.log(exception);
             }
             setStatus("Exited");
         };