There were a bunch of helper scripts to build a go tool and run it.
Replace these with a single 'run' command that takes the tool name and arguments.
Helps reduce maintainance, file spew.
Also add the 'tools/bin' directory to .gitignore. These are the cached tool binaries.
Bug: dawn:1339
Change-Id: I012c966736b4d93949f6142c342cdcfefa9f0083
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/86063
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Ben Clayton <bclayton@google.com>