Made DSLType::Array return poison on error
Made DSLType::Array return poison on error

This fixes spurious errors that occur subsequent to an error converting
and array size.

Change-Id: I23fda9ef744f9144726d4fd28584676b33a4c7bb
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/444177
Reviewed-by: Brian Osman <794c0b5534edf5601d88e1d41975d0262da12894@google.com>
Commit-Queue: Ethan Nicholas <d2cfb8c2f603266f4dc3a6f09acbcc0089603b37@google.com>

google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia