fix Issue 12382 - `opDollar` can't be used at CT

Front-end should handle opDollar side-effect carefully, because CTFE engine cannot interpret `(auto __dollar = obj.opDollar(), obj).opIndex(__dollar)` without CTFE stack.
Merge pull request #3385 from 9rnsr/fix12382

Issue 12382 - `opDollar` can't be used at CT