By removing inactive uniforms in the translator, glslang wrapper doesn't
need to comment them out.  Additionally, inactive uniforms don't find
their way in the default uniform block, reducing its size if there's a
mix of active and inactive uniforms.

As collateral, it also fixes a bug where inactive uniforms of struct
type were not correctly removed by glslang wrapper.

Bug: angleproject:3394
Bug: angleproject:4211
Bug: angleproject:4248
Change-Id: I874747070e875fe24bf59d39d1322e319e280a16
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1999278
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>