Wayland: Fix EGL buffer swap blocking indefinitely

When the swap interval was nonzero, EGL on Wayland would wait
indefinitely for a frame callback on a suspended window, causing
applications that call eglSwapBuffers to halt.

This re-implements the wait for a surface frame so that we can add
a reasonable timeout, while setting the EGL swap interval to zero.  That
allows applications to make progress despite the window being suspended.

Some insights for how to structure this workaround were gleaned from
dri2_wl_swap_buffers_with_damage in Mesa.

This initial implementation still has a race between glfwHideWindow and
glfwSwapBuffers when rendering on a separate thread.  This could lead to
a window becoming visible again after being hidden on the main thread.

Related to #1350
Fixes #2582
Fixes #2640
Fixes #2719
Fixes #2723
Fixes #2800
Fixes #2827

include/GLFW/glfw3.h

@@ -6174,6 +6174,10 @@ GLFWAPI GLFWwindow* glfwGetCurrentContext(void);
  *  @errors Possible errors include @ref GLFW_NOT_INITIALIZED, @ref
  *  GLFW_NO_WINDOW_CONTEXT and @ref GLFW_PLATFORM_ERROR.
  *
+ *  @remark __Wayland:__ When the swap interval is greater than zero and the
+ *  window is not in view, this function may take a few extra milliseconds to
+ *  return.
+ *
  *  @remark __EGL:__ The context of the specified window must be current on the
  *  calling thread.
  *