core/memory/arena: Add context Get() Put() functions.
core/memory/arena: Add context Get() Put() functions.

Putting arenas in contexts is going to be A Thing™.

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