Convert interpreter "compound types" test to SkVM

This is the first test that used uniform data, so fix up how uniforms
work in the generic SkSL-to-SkVM function.

Bug: skia:11094
Bug: skia:11096
Change-Id: Ie391c1a6b8b68f0f4f014d7e767d7b5101341fab
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/352739
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
3 files changed