Fixes some bugs in IOSurface

[webner]

This PR fixes some IOSurface bugs on MacOS.

• The fetchGLTexId method did not work when JavaFX activated another texture unit.
• Restores the state of the SCISSOR_TEST and restores the active texture

[webner]

@husker-dev can you take a look at this?

[husker-dev]

Hi,
I knew that in IOSurface some OpenGL variables change during manipulations. But is it so critical?
In test cases, there were no problems. Have you encountered cases where it did not work?

Especially interesting with glEnable(GL_SCISSOR_TEST) - I think it is enabled by default in JavaFX, so checking may be unnecessary.

[webner]

GL_SCISSOR_TEST is not always enabled. It is disabled when the clipRect is null or empty.
See https://github.com/openjdk/jfx/blob/dcfe56bd87ab9160d90b4b0aa634ca0b41788283/modules/javafx.graphics/src/main/java/com/sun/prism/es2/ES2Context.java#L318

[husker-dev]

Thank you, I see

[webner]

Thanks. Could you also create a new release with the last fixes?

[husker-dev]

Launched build 4.1.19, in about 20 minutes you can use it