Add unit test demonstrating recursion codegen bug.

The generated code does not assign to sk_OutColor correctly; it assigns
into the `factorial` function name instead, which doesn't make sense.

Change-Id: Ibad1d47f2f9c4fbb410b5277cea6e1022daf8b9d
Bug: skia:10684
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/329360
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
4 files changed