unconditional_panic array bounds check doesn't work through Deref

[e2-71828]

(Initially reported on URLO)

In the following program:

fn main() {
    let mut arr_0: [u32; 10] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];

    let ptr_0 = Box::new(arr_0);

    let ptr_v = ptr_0[11];
    let arr_v = arr_0[11];
    println!("v:{}", ptr_v);
}

The out-of-bounds access of ptr_0[11] is not flagged at compile time, but the similar access of arr_0[11] is.

[clubby789]

It looks like the MIR ends up as

_7 = const false;
assert(move _7, "index out of bounds: the length is {} but the index is {}", move _6, _5) -> [success: bb2, unwind: bb4];

and the lint isn't able to look through that constant to identify it

[veera-sivarajan]

Fixed by #129517: https://rust.godbolt.org/z/YqKf4YhK3