Remove `pre` and `out` parameters from most generator methods.
Use the `out_` string stream in TextGenerator, add helpers to TextGenerator to simplify line printing.
Remove the `pre` and `out` fields from TestHelper.
Cleans up the `pre` aspects of the HLSL writer, so the same concept can be used by the MSL writer.
Fixes indentation bugs in formatting.
Change-Id: Ia35daf632c7c7b84a6fbf3b9ae42baaeb3c97649
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/55960
Auto-Submit: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: David Neto <dneto@google.com>
Reviewed-by: James Price <jrprice@google.com>
Ben Clayton