Emit top-level StructDefinition for every struct

Previously, structs that were defined as part of a variable declaration
would end up declared similarly in the generated code. Now, global
variable declarations that include a struct definition generate two
separate program elements.

Bug: skia:11228
Change-Id: Id7ddde6931fe07a250c2c9c46153879005535fb3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/361359
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
9 files changed