Allow pre/post-increment on vectors and matrices.

This is explicitly required by the GLSL expression rules (5.9):

> The arithmetic unary operators negate (-), post-and pre-increment
> and decrement (-- and ++) operate on integer or floating-point
> values (including vectors and matrices).

This CL allows vector and matrix types in the frontend, and adds
tests. Backend support has been added in earlier CLs.

Bug: b/40045109
Change-Id: I0d4a817eece833234abe1369ec146922a5adb0f6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/845301
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
19 files changed