[CIR][AArch64][Lowering] Support fields with structs containing constant arrays or pointers

[bruteforceboy]

This PR adds support for function arguments with structs that contain constant arrays or pointers for AArch64.

For example,

typedef struct {
  int a[42];
} CAT;

void pass_cat(CAT a) {}

As usual, the main ideas are gotten from the original CodeGen, and I have added a couple of tests.

[smeenai]

Should we also add a test for a struct containing a smaller array (which should be passed via registers instead of pointer)?

[bruteforceboy]

Should we also add a test for a struct containing a smaller array (which should be passed via registers instead of pointer)?

IMHO, the test is okay as it is) The main idea of the PR is adding support for the types because of the "NYI" fail previously. The sizes or how it is passed doesn't really matter (for this PR at least).

[smeenai]

Checking for different array sizes would get some coverage for the size calculation e.g. making sure that int[4] is passed in registers but long[4] isn't. You're right that it's not strictly necessary here though.