An alwaysinline function may not get inlined in inliner-wrapper due to
the inlining order.

Previously for the following, the inliner would first inline @a() into @b(),

```
define void @a() {
entry:
  call void @b()
  ret void
}

define void @b() alwaysinline {
entry:
  br label %for.cond

for.cond:
  call void @a()
  br label %for.cond
}
```

making @b() recursive and unable to be inlined into @a(), ending at

```
define void @a() {
entry:
  call void @b()
  ret void
}

define void @b() alwaysinline {
entry:
  br label %for.cond

for.cond:
  call void @b()
  br label %for.cond
}
```

Running always-inliner first makes sure that we respect alwaysinline in more cases.

Fixes https://bugs.llvm.org/show_bug.cgi?id=46945.

Reviewed By: davidxl, rnk

Differential Revision: https://reviews.llvm.org/D86988