…9100)

Under some conditions, a trivial `mov xN xN` instruction was emitted on
tail calls. Consider the following code:

```
class Test {
public:
  virtual void f() {}
};

void call_f(Test *t) {
  t->f();
}
```

Correponding assembly:

```
_Z6call_fP4Test:
        ldr     x16, [x0]
        mov     x17, x0
        movk    x17, #6503, lsl #48
        autda   x16, x17
        ldr     x1, [x16]
 =====> mov     x16, x16
        movk    x16, llvm#54167, lsl #48
        braa    x1, x16
```

This patch makes such movs being omitted.

Co-authored-by: Anatoly Trosinenko <atrosinenko@accesssoftek.com>