Fix a no match for 'operator!' error in the WebProcess/GPU/graphics/gbm/RemoteGraphicsContextGLProxyGBM.cpp
Pull request: https://github.com/WebKit/WebKit/pull/20666
Committed 270962@main (1164de267e81): <https://commits.webkit.org/270962@main> Reviewed commits have been landed. Closing PR #20666 and removing active labels.
<rdar://problem/118639802>