Simplify prepareSpec(). (#116)

`ExprTools.map()` already iterates through blocks and replaces their
contents, so there's no need to type out our own loop.

src/utest/utils/TestBuilder.hx

@@ -275,19 +275,10 @@ class TestBuilder {
 
  static function prepareSpec(expr:Expr) {
  return switch(expr.expr) {
- case EBlock(exprs):
- var newExprs = [];
- for(expr in exprs) {
- switch(expr.expr) {
- case EBinop(op, left, right):
- newExprs.push(parseSpecBinop(expr, op, left, right));
- case EUnop(op, prefix, subj):
- newExprs.push(parseSpecUnop(expr, op, prefix, subj));
- case _:
- newExprs.push(ExprTools.map(expr, prepareSpec));
- }
- }
- {expr:EBlock(newExprs), pos:expr.pos};
+ case EBinop(op, left, right):
+ parseSpecBinop(expr, op, left, right);
+ case EUnop(op, prefix, subj):
+ parseSpecUnop(expr, op, prefix, subj);
  case _:
  ExprTools.map(expr, prepareSpec);
  }