[spreads][refactor] Split out mk_object from spread and put it in ObjectExpressionAcc
[spreads][refactor] Split out mk_object from spread and put it in ObjectExpressionAcc

Summary: The object is created almost entirely out of the information carried about by ObjectExpressionAcc. We should move the object creation there instead. In the next diff, I'll call into the same code to create objects out of JSX props.

Reviewed By: dsainati1

Differential Revision: D18306721

fbshipit-source-id: 181d35824715d53db5594f6b1fc7fba506314cb5

nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow