This results in significant improvement to type-checking time:
it reduces by 4% the entire running time of ssa/stdlib_test
(GOMAXPROCS=8, n=7).
LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/57770043
CL 49530047 made the (over-)simplifying assumption that the
Path of an ad-hoc (Created) package should default to its
Name, i.e. package declaration.
With this change, the Name is still always computed from the
package declaration (by go/types) but the Path may be
specified by the loader.Config. If "", the value of the Name
is used, which is not globally unique.
R=gri, axwalk
CC=golang-codereviews
https://golang.org/cl/55180043
Alan Donovan