Rename to 'gen', so that more templating can be added without having a confusing name.
Can now be run with './tools/run gen'
Move the bulk of the intrinsic-gen logic to `tools/src/tint/intrinsic`
Change-Id: I750989a5aa86272c10c2ad37adffe7def11c61f2
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/97141
Commit-Queue: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>