[wasm] Implement official wasm text format

src/wasm/ast-decoder.h

Index: src/wasm/ast-decoder.h
diff --git a/src/wasm/ast-decoder.h b/src/wasm/ast-decoder.h
index 9ce323efcbab6d917e75f166d47637d2e70c3e05..dfdc377f76ae7e64cfee1a8842679f3c48ac634f 100644
--- a/src/wasm/ast-decoder.h
+++ b/src/wasm/ast-decoder.h
@@ -243,10 +243,6 @@ struct BranchTableOperand {
     }
     table = pc + 1 + len1;
   }
-  inline uint32_t read_entry(Decoder* decoder, unsigned i) {
-    DCHECK(i <= table_count);
-    return table ? decoder->read_u32(table + i * sizeof(uint32_t)) : 0;
-  }
 };
 
 // A helper to iterate over a branch table.