Rollup merge of rust-lang#154574 - cyrgani:less-const-tests, r=Kivooeo

delete several `ui/consts` tests

* `tests/ui/consts/const.rs`: meaningless
* `tests/ui/consts/const-bound.rs`: has nothing to do with const bounds or const at all (anymore?)
* `tests/ui/consts/const-enum-tuplestruct2.rs`, `tests/ui/consts/const-enum-tuple2.rs`, `tests/ui/consts/const-enum-tuple.rs`: duplicates of `tests/ui/consts/const-enum-tuplestruct.rs`
r? @Kivooeo

Author: tgross35