Fix BitShift UB when shift amount >= bit width (#28272)
### Description
Shifting by >= the bit width of an unsigned type is undefined behavior
in C++. On x86-64, the hardware masks 64-bit shift amounts to 6 bits, so
`x >> 64` silently becomes `x >> 0`, returning the original value
instead of 0.
Added `SafeShiftLeft`/`SafeShiftRight` helpers that return 0 when `shift
>= sizeof(T) * 8`, applied across all three broadcast code paths
(scalar-X, scalar-Y, element-wise).
```cpp
template <typename T>
inline T SafeShiftRight(T value, T shift) {
return shift >= sizeof(T) * 8 ? T{0} : value >> shift;
}
```
Added tests covering:
- Shift by exact bit width (32, 64) for `uint32_t` and `uint64_t`
- Shift by more than bit width (65, 128)
- All three broadcast paths (scalar-X, scalar-Y, element-wise)
- New tests are excluded for DirectML EP, which has the same
hardware-level shift masking behavior
### Motivation and Context
`BitShift` with `direction="RIGHT"` on `uint64` inputs with shift amount
64 returns the original values instead of zeros. Reproduces with
`CPUExecutionProvider` and `ORT_DISABLE_ALL` (constant folding masks the
bug under `ORT_ENABLE_ALL`).
---------
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: tianleiwu <30328909+tianleiwu@users.noreply.github.com>
