[AArch64] Add intrinsics for bfloat16 min/max/minnm/maxnm (#90105)

According to specifications in
[ARM-software/acle/pull/309](https://github.com/ARM-software/acle/pull/309)
Add following intrinsics:

```
// svmax single,multi
svbfloat16x2_t svmax_single_bf16_x2(svbfloat16x2_t zdn, svbfloat16_t zm)
svbfloat16x4_t svmax_single_bf16_x4(svbfloat16x4_t zdn, svbfloat16_t zm)
svbfloat16x2_t svmax_bf16_x2(svbfloat16x2_t zdn, svbfloat16x2_t zm)
svbfloat16x4_t svmax_bf16_x4(svbfloat16x4_t zdn, svbfloat16x4_t zm)
```

```
// svmin single,multi
svbfloat16x2_t svmin_single_bf16_x2(svbfloat16x2_t zdn, svbfloat16_t zm)
svbfloat16x4_t svmin_single_bf16_x4(svbfloat16x4_t zdn, svbfloat16_t zm)
svbfloat16x2_t svmin_bf16_x2(svbfloat16x2_t zdn, svbfloat16x2_t zm)
svbfloat16x4_t svmin_bf16_x4(svbfloat16x4_t zdn, svbfloat16x4_t zm)
```

```
// svmaxnm single,multi
svbfloat16x2_t svmaxnm_single_bf16_x2(svbfloat16x2_t zdn, svbfloat16_t zm)
svbfloat16x4_t svmaxnm_single_bf16_x4(svbfloat16x4_t zdn, svbfloat16_t zm)
svbfloat16x2_t svmaxnm_bf16_x2(svbfloat16x2_t zdn, svbfloat16x2_t zm)
svbfloat16x4_t svmaxnm_bf16_x4(svbfloat16x4_t zdn, svbfloat16x4_t zm)
```

```
// svminnm single,multi
svbfloat16x2_t svminnm_single_bf16_x2(svbfloat16x2_t zdn, svbfloat16_t zm)
svbfloat16x4_t svminnm_single_bf16_x4(svbfloat16x4_t zdn, svbfloat16_t zm)
svbfloat16x2_t svminnm_bf16_x2(svbfloat16x2_t zdn, svbfloat16x2_t zm)
svbfloat16x4_t svminnm_bf16_x4(svbfloat16x4_t zdn, svbfloat16x4_t zm)
```
- Variations other than bfloat16 are already supported.