Revert "added nodehash.h change for previous commit"

This reverts commit 09ba568cbe0f9ffdd478f274948c28ab8788fe88.
Revert "change in node hash logic, nodehash.c and nodeHashJoin.c and execnodes.h"

This reverts commit 79bd482bf875f518f44c9a8804d78b829aa3d759.
here goes nothing