Add SPIR-V support for doubly-swizzled lvalues.

This fixes the OutParamsTricky test.

Change-Id: If59637bc946b71b141ae1d90cf1652bf80b163c4
Bug: skia:11269
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/366399
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
5 files changed