wasm: support setting environment again

After enabling -s MODULARIZE=1 there is no longer a
global ENV. Use module.ENV instead.

Change-Id: Ic6958f52c6ceb7014f7f2c78a73f2bce5a43bf41
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

src/plugins/platforms/wasm/qtloader.js

@@ -416,7 +416,7 @@ function QtLoader(config)
         self.moduleConfig.preRun.push(function(module) {
             // Set environment variables
             for (var [key, value] of Object.entries(config.environment)) {
-                ENV[key.toUpperCase()] = value;
+                module.ENV[key.toUpperCase()] = value;
             }
             // Propagate Qt module properties
             module.qtCanvasElements = self.qtCanvasElements;