Remove duplicate geqo functions, and more optimizer cleanup

src/backend/nodes/copyfuncs.c

src/backend/nodes/equalfuncs.c

src/backend/nodes/freefuncs.c

src/backend/nodes/outfuncs.c

src/backend/optimizer/geqo/Makefile

src/backend/optimizer/geqo/geqo_eval.c

src/backend/optimizer/geqo/geqo_params.c

src/backend/optimizer/geqo/geqo_paths.c

src/backend/optimizer/path/allpaths.c

src/backend/optimizer/path/costsize.c

src/backend/optimizer/path/indxpath.c

src/backend/optimizer/path/joinpath.c

src/backend/optimizer/path/joinrels.c

src/backend/optimizer/path/mergeutils.c

src/backend/optimizer/path/prune.c

src/backend/optimizer/plan/initsplan.c

src/backend/optimizer/plan/planmain.c

src/backend/optimizer/util/joininfo.c

src/backend/optimizer/util/pathnode.c

src/backend/optimizer/util/relnode.c