This adds a simple go program to test the installed go
toolchain, and a Make rule to codify the arguments to
our gazelle binary, built with extensions.
I could not figure out how to get the .json file to work
with the gazelle() Bazel rule, but this works ok for now.
Bug: skia:12541
Change-Id: I5067b15c7518951aeb69559d3871799d3b5745f4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/475716
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
