[EH] Make tag's attribute encoding detail (#3947)

This removes `attribute` field from `Tag` class, making the reserved and
unused field known only to binary encoder and decoder. This also removes
the `attribute` parameter from `makeTag` and `addTag` methods in
wasm-builder.h, C API, and Binaryen JS API.

Suggested in
https://github.com/WebAssembly/binaryen/pull/3946#pullrequestreview-687756523.

1 files changed, 1 insertions, 3 deletions

diff --git a/src/wasm-builder.h b/src/wasm-builder.h
index ca3fed286..a3b0febaa 100644
--- a/src/wasm-builder.h
+++ b/src/wasm-builder.h
@@ -125,11 +125,9 @@ public:
     return glob;
   }
 
-  static std::unique_ptr<Tag>
-  makeTag(Name name, uint32_t attribute, Signature sig) {
+  static std::unique_ptr<Tag> makeTag(Name name, Signature sig) {
     auto tag = std::make_unique<Tag>();
     tag->name = name;
-    tag->attribute = attribute;
     tag->sig = sig;
     return tag;
   }