Fix modifiers on InterfaceBlocks in description().

Previously, these were silently dropped. We didn't have any DSL tests
for InterfaceBlock modifiers (which is where `description()` usually
gets tested).

Change-Id: I49d87df50d44aeaa4e00182f82ece6720b5a9426
Bug: skia:13775
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/585968
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
3 files changed