Shift EmbedderState values next to each other

For consistency with the other enums values, avoid gaps between
EmbedderState values.

Bug: chromium:1263871
Change-Id: I22c58700f292b007ced7c12db219f578f82d77d1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3370081
Auto-Submit: Corentin Pescheloche <cpescheloche@fb.com>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78549}

include/v8-embedder-state-scope.h

@@ -19,9 +19,10 @@ class EmbedderState;
 
 // A StateTag represents a possible state of the embedder.
 enum class EmbedderStateTag : uint8_t {
+  // reserved
   EMPTY = 0,
-  // embedder can define any state in between
-  OTHER = UINT8_MAX,
+  OTHER = 1,
+  // embedder can define any state after
 };
 
 // A stack-allocated class that manages an embedder state on the isolate.