gles: Fix cloning logic of the context in compat.
gles: Fix cloning logic of the context in compat.

Despite the name `deep.Clone` cannot clone private fields of structs. This includes the thread.

Fixes compat for OpenGL 2.0 captures.

google/agi,google/gapid,baldwinn860/gapid,pmuetschard/gapid,google/agi,Qining/gapid,pmuetschard/gapid,pmuetschard/gapid,Qining/gapid,pmuetschard/gapid,google/agi,google/agi,google/gapid,baldwinn860/gapid,Qining/gapid,baldwinn860/gapid,google/gapid,google/gapid,pmuetschard/gapid,baldwinn860/gapid,baldwinn860/gapid,google/gapid,Qining/gapid,Qining/gapid,google/agi,pmuetschard/gapid,Qining/gapid,baldwinn860/gapid,google/gapid,google/agi,pmuetschard/gapid,Qining/gapid,baldwinn860/gapid,pmuetschard/gapid,baldwinn860/gapid,google/gapid,google/gapid,google/agi,Qining/gapid,google/agi