[dawn] Consider stream decode errors Internal.

Change the stream errors from Validation to Internal. If the stream
fails to decode that's an error in either what we wrote or how we read
the data.

Bug: 536639352
Change-Id: Id4c4f79cb317f067952ea8118fb746f102f5c08c
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/342496
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Loko Kung <lokokung@google.com>
Commit-Queue: dan sinclair <dsinclair@chromium.org>

src/dawn/native/stream/Stream.h

diff --git a/src/dawn/native/stream/Stream.h b/src/dawn/native/stream/Stream.h
index a20fd58..1298976 100644
--- a/src/dawn/native/stream/Stream.h
+++ b/src/dawn/native/stream/Stream.h
@@ -627,7 +627,7 @@
         size_t typeId;
         DAWN_TRY(StreamOut(source, &typeId));
         if (typeId >= sizeof...(Types)) {
-            return DAWN_VALIDATION_ERROR("Invalid variant type id");
+            return DAWN_INTERNAL_ERROR("Invalid variant type id");
         } else {
             return ReadImpl<0, Types...>(source, t, typeId);
         }