translate-c: fix function pointer casting + alignCast and constCast at the same time

[paokitore]

This fixes #24513 and another issue I noticed: casting const void* to int* did not work.

Both of those issues are fixed with translate-c, so this PR might be useless though.

examples:

void *g = (void*)f;

used to translate to:

var g: ?*anyopaque = @as(?*anyopaque, @ptrCast(f));

forgetting a @constCast.

and

const void *c;
int *d = (int*)c;

the second line used to translate to:

var d: [*c]c_int = @as([*c]c_int, @ptrCast(@volatileCast(@constCast(c))));

forgetting a @alignCast.

[alexrp]

This would effectively be made obsolete by #24497, so I think we'd only consider taking this PR if #24497 for some reason fails to land in 0.15.0.