[AArch64][SME] Extend Inliner cost-model with custom penalty for calls. (#68416)

This is a stacked PR following on from #68415 

This patch has two purposes:
(1) It tries to make inlining more likely when it can avoid a
streaming-mode change.
(2) It avoids inlining when inlining causes more streaming-mode changes.

An example of (1) is:
```
  void streaming_compatible_bar(void);

  void foo(void) __arm_streaming {
    /* other code */
    streaming_compatible_bar();
    /* other code */
  }

  void f(void) {
    foo();            // expensive streaming mode change
  }

  ->

  void f(void) {
    /* other code */
    streaming_compatible_bar();
    /* other code */
  }
```
where it wouldn't have inlined the function when foo would be a
non-streaming function.

An example of (2) is:
```
  void streaming_bar(void) __arm_streaming;

  void foo(void) __arm_streaming {
    streaming_bar();
    streaming_bar();
  }

  void f(void) {
    foo();            // expensive streaming mode change
  }

  -> (do not inline into)

  void f(void) {
    streaming_bar();  // these are now two expensive streaming mode changes
    streaming_bar();
  }```