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