redundant calls to finish() in wasm render method

[cmyr]

Not sure exactly what's going on here, but it looks a bit suspicious:

I am not sure why we need to finish calls. For reference, I believe the code @jneem is referring to is in the render function

fn render(&self) -> bool {
    self.context
        .clear_rect(0.0, 0.0, self.get_width() as f64, self.get_height() as f64);
    let mut piet_ctx = piet_common::Piet::new(self.context.clone(), self.window.clone());
    let want_anim_frame = self.handler.borrow_mut().paint(&mut piet_ctx);
    if let Err(e) = piet_ctx.finish() {
        log::error!("piet error on render: {:?}", e);
    }
    let res = piet_ctx.finish();
    if let Err(e) = res {
        log::error!("EndDraw error: {:?}", e);
    }
    want_anim_frame
}

This part is over a year old. It does look redundant to me. After trying the examples without the second piet_ctx.finish(), I couldn't find any difference. I think it's safe to remove the second .finish() call.

Originally posted by @elrnv in #817 (comment)