Try to use non-volatile registers for `preserve_none` parameters (#88333)

This uses non-volatile registers for the first four (six on Windows)
registers used for `preserve_none` argument passing. This allows these
registers to stay "pinned", even if the body of the `preserve_none`
function contains calls to other "normal" functions.

Example:

```c
void boring(void);

__attribute__((preserve_none)) void (continuation)(void *, void *, void *, void *);

__attribute__((preserve_none)) void entry(void *a, void *b, void *c, void *d)
{
    boring();
    __attribute__((musttail)) return continuation(a, b, c, d);
}
``` 

Before:

```asm
pushq   %rax
movq    %rcx, %rbx
movq    %rdx, %r14
movq    %rsi, %r15
movq    %rdi, %r12
callq   boring@PLT
movq    %r12, %rdi
movq    %r15, %rsi
movq    %r14, %rdx
movq    %rbx, %rcx
popq    %rax
jmp     continuation@PLT
```

After:

```asm
pushq   %rax
callq   boring@PLT
popq    %rax
jmp     continuation@PLT
```