GLFW glfwGetFramebufferSize() and glfwGetWindowSize()

Looks like the `glfwGetWindowSize` and `glfwGetFramebufferSize` methods are returning the same value although the canvas native and normal dimensions are different. From my understanding, the `glfwGetFramebufferSize` should report the `Module.canvas.[width, height]` and `glfwGetWindowSize` should report the `Module.canvas.[widthNative, heightNative]`. But right now, both functions are reporting the `Module.canvas.[width, height]` value.

Reporting the correct size is particularly important for HiDPI applications. Third-party libraries like ImGui use these functions in many places, making it difficult to fix without modifying Emscripten.