Revert "accept naked exprs with commas in pattern arms" due to pretty-printing failures

This reverts commit f712b2d76b.

In alt arms, the parser needs to do a little lookahead to determine
whether it's looking at a record literal or a block.

Also there are some indentation issues in the expected source.

src/libsyntax/ast_util.rs

@@ -568,13 +568,6 @@ fn view_path_id(p: @view_path) -> node_id {
     }
 }
 
-fn lone_block_expr(blk: blk) -> option<@ast::expr> {
-    if blk.node.view_items.len() != 0 { ret none; }
-    if blk.node.stmts.len() != 0 { ret none; }
-    if blk.node.rules != default_blk { ret none; }
-    ret blk.node.expr;
-}
-
 // Local Variables:
 // mode: rust
 // fill-column: 78;