[AArch64][SME] Add pass remarks to the MachineSMEABIPass (#170277)

This patch implements SME ABI pass remarks for when:

* a lazy ZA save is set up
* a full/agnostic ZA save is set up
* a ZT0 spill is emitted

These remarks can be enabled with `--pass-remarks-analysis=sme` (like
the current SME remarks).

The remarks work by noting where the save/spill was emitted, then
pointing out calls later in the function that require the save. The
remarks stop at the first call found along any path.

For example:

```
 7:  void merge_paths(bool a) __arm_inout("za") {
 8:    if (a)
 9:      private_za_callee_a();
10:    else
11:      private_za_callee_b();
12:    private_za_callee_c(); // no remark (does not require a new save)
13:  }
```

Results in the following remarks:

```
remark: foo.c:8:7: lazy save of ZA emitted in 'merge_paths'
remark: foo.c:9:5: call to 'private_za_callee_a' requires ZA save
remark: foo.c:11:5: call to 'private_za_callee_b' requires ZA save
```