so that == on func means that the
functions originated in the same
execution of a func literal or definition.
before, there was an inconsistency:
func() {x++} != func() {x++}
but
func() {} == func() {}
this CL makes the second case != too,
just like
make(map[int]int) != make(map[int]int)
R=r
DELTA=202 (71 added, 62 deleted, 69 changed)
OCL=32393
CL=32398
