GraphicsContextGLANGLE subclasses duplicate context state initialization
<rdar://problem/117410801>
Pull request: https://github.com/WebKit/WebKit/pull/19480
Committed 269758@main (6c5d9dcd77c9): <https://commits.webkit.org/269758@main> Reviewed commits have been landed. Closing PR #19480 and removing active labels.