This change enables the ComputeShaderTest suite and additionally
includes the following fixes:

- OpArrayLength was given the array type instead of variable.
- Struct arrays inside interface blocks were not decorated with
  ArrayStride.

Bug: angleproject:4889
Change-Id: Ibae95371bcea10e58c86b8fe1d1e172a18d56a09
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3001908
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>