Array indexing in DSLX interpreter does not match IR behavior

**Describe the bug**
The DSLX interpreter will error when the array index is out of bounds:

https://github.com/google/xls/blob/c59b6a21b8bc362f2899706bd74eb8ea7708644f/xls/dslx/interp_value.cc#L675-L683

However, as discussed in https://github.com/google/xls/discussions/1494, the IR documentation states:

> Any out-of-bounds indices idx_{i} are clamped to the maximum in bounds index for the respective dimension.

**To Reproduce**

```
fn foo(arr: u32[10], idx: u32) -> u32 {
arr[idx]
}

#[test]
fn foo_test() {
assert_eq(foo(u32[10]:[u32:1, ...], u32:11), u32:1);
}
```

yields the error:

> INVALID_ARGUMENT: Index out of bounds; index: 11 >= 10 elements; lhs: [u32:1, u32:1, u32:1, u32:1, u32:1, u32:1, u32:1, u32:1, u32:1, u32:1];