Remove fields that are dead since the removal of type ascription syntax

Since `{ ident: ident }` is a parse error, these fields are dead.

compiler/rustc_parse/src/parser/stmt.rs

@@ -1043,14 +1043,7 @@ impl<'a> Parser<'a> {
         rules: BlockCheckMode,
         span: Span,
     ) -> P<Block> {
-        P(Block {
-            stmts,
-            id: DUMMY_NODE_ID,
-            rules,
-            span,
-            tokens: None,
-            could_be_bare_literal: false,
-        })
+        P(Block { stmts, id: DUMMY_NODE_ID, rules, span, tokens: None })
     }
 
     pub(super) fn mk_stmt(&self, span: Span, kind: StmtKind) -> Stmt {