Moved the code which generates static.go to remain in the static package.
This makes the code testable.
Additionally, it is very easy for developers to forget to run "go generate"
to update static.go. Because while development, the templates directory
can be directly passed as a flag to read the files from it.
This test catches that.
Change-Id: I314907b98907bb14e4eabfd3c532ba2d84ce7c5f
Reviewed-on: https://go-review.googlesource.com/110158
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
