glx: add make and copy bad access checks
The GLX spec for glXMakeCurrent (3.3): "If ctx is current to some other thread, then glXMakeCurrent will generate a BadAccess error"
The GLX spec for glXCopyContext (3.3): "If the destination context is current for some thread then a BadAccess error is generated"
Mesa MR with this checks: mesa!22546 (merged)
Signed-off-by: Illia Polishchuk illia.a.polishchuk@globallogic.com