Implement some advance blending equation in GLEngine by using two
RenderPass.
* The first pass render the content into an off-screen framebuffer, also
blit the screen content to an off-screen Texture.
* The second pass renders the final blended color to the screen.
Also use a stencil test to prevent non-drawn areas from participating in the color blending calculation.
issue: https://github.com/thorvg/thorvg/issues/2435
Performing a full-screen RenderPass resolve is too expensive.
Because most composite cases only require a small area to be rendered off-screen.
To improve performance, use the bounds of the Geometry for off-screen rendering whenever possible
* Optimize clip logical, change to use GL_GRATER and keep incrace depth
value, so no need to do depth clear after every clip draw.
* Correct geometry bounding box calculation, and make sure the bounds is
larger than all vertices
* Limit drawing area for off-screen RenderPass with correct scissor box
* use GLRenderBuffer in color and stencil attachment, also use x4 sample
count by default.
* add msaa resolve logical at the end of a ComposeTask, so the normal
color texture can get the final rendering result.
