Method-set caching is now performed externally using a MethodSetCache (if desired), not by the Types themselves.
This a minor deoptimization due to the extra maps, but avoids a situation in which method-sets are computed and frozen prematurely. (See b/7114)
LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/61430045
Since Put() makes a dynamic function call, this CL includes a long-overdue change to supply a *frame (and thus the call
stack and the interpreter) to intrinsics too.
This fixes the tests that were broken by (sound) revision e4a4cb47c141.
LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/57350043
Alan Donovan