Remove redundant setting of Module.ctx. NFC (#22858)

The `Browser.createContext` function already sets `Module.ctx` when
`setInModule` is used.

Author: sbc100

src/library_glfw.js

@@ -1101,7 +1101,7 @@ var LibraryGLFW = {
           // TODO: Make GLFW explicitly aware of whether it is being proxied or not, and set these to true only when proxying is being performed.
           GL.enableOffscreenFramebufferAttributes(contextAttributes);
 #endif
-          Module.ctx = Browser.createContext(Module['canvas'], true, true, contextAttributes);
+          Browser.createContext(Module['canvas'], /*useWebGL=*/true, /*setInModule=*/true, contextAttributes);
         } else {
           Browser.init();
         }

src/library_glut.js

@@ -566,8 +566,9 @@ var LibraryGLUT = {
     // TODO: Make glutCreateWindow explicitly aware of whether it is being proxied or not, and set these to true only when proxying is being performed.
     GL.enableOffscreenFramebufferAttributes(contextAttributes);
 #endif
-    Module.ctx = Browser.createContext(Module['canvas'], true, true, contextAttributes);
-    return Module.ctx ? 1 /* a new GLUT window ID for the created context */ : 0 /* failure */;
+    if (!Browser.createContext(Module['canvas'], /*useWebGL=*/true, /*setInModule=*/true, contextAttributes))
+      return 0; // failure
+    return 1; // a new GLUT window ID for the created context
   },
 
   glutDestroyWindow__proxy: 'sync',