Rollup merge of #74491 - xldenis:constant-binop-opt, r=oli-obk

Optimize away BitAnd and BitOr when possible

This PR lets `const_prop` optimize away `a | true == true` , `a & false == false` and `a * 0 = 0`. While I was writing this I've realized that constant propagation misses a lot of opportunities. For example:  https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=2a4b45e772f214210a36749b27223bb0

Constant propagation doesn't seem to... propagate constants, additionally the way constant propagation is currently setup makes it tricky to add cases like `a | false == a`.

I tried to organize `eval_rvalue_with_identities` to make the pattern of the optimizations easier to see but it still obscurs what should be a simple peephole optmization.

cc @oli-obk

src/test/ui/consts/const-eval/index-out-of-bounds-never-type.rs

@@ -1,7 +1,7 @@
 // build-fail
 
 // Regression test for #66975
-#![warn(const_err)]
+#![warn(const_err, unconditional_panic)]
 #![feature(never_type)]
 
 struct PrintName<T>(T);
@@ -9,6 +9,7 @@ struct PrintName<T>(T);
 impl<T> PrintName<T> {
     const VOID: ! = { let x = 0 * std::mem::size_of::<T>(); [][x] };
     //~^ WARN any use of this value will cause an error
+
 }
 
 fn f<T>() {

src/test/ui/consts/const-eval/index-out-of-bounds-never-type.stderr

@@ -9,11 +9,11 @@ LL |     const VOID: ! = { let x = 0 * std::mem::size_of::<T>(); [][x] };
 note: the lint level is defined here
   --> $DIR/index-out-of-bounds-never-type.rs:4:9
    |
-LL | #![warn(const_err)]
+LL | #![warn(const_err, unconditional_panic)]
    |         ^^^^^^^^^
 
 error: erroneous constant encountered
-  --> $DIR/index-out-of-bounds-never-type.rs:15:13
+  --> $DIR/index-out-of-bounds-never-type.rs:16:13
    |
 LL |     let _ = PrintName::<T>::VOID;
    |             ^^^^^^^^^^^^^^^^^^^^