Auto merge of #14787 - HKalbasi:mir2, r=HKalbasi

MIR episode 5

This PR inits drop support (it is very broken at this stage, some things are dropped multiple time, drop scopes are wrong, ...) and adds stdout support (`println!` doesn't work since its expansion is dummy, but `stdout().write(b"hello world\n")` works if you use `RA_SYSROOT_HACK`) for interpreting. There is no useful unit test that it can interpret yet, but it is a good sign that it didn't hit a major road block yet.

In MIR lowering, it adds support for slice pattern and anonymous const blocks, and some fixes so that we can evaluate `SmolStr::new_inline` in const eval. With these changes, 57 failed mir body remains.

crates/test-utils/src/minicore.rs

@@ -324,6 +324,13 @@ pub mod mem {
         }
     }
 }
+
+pub mod ptr {
+    #[lang = "drop_in_place"]
+    pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
+        unsafe { drop_in_place(to_drop) }
+    }
+}
 // endregion:drop
 
 pub mod ops {