* Sema: Correctly determine whether array_cat lhs and rhs are single ptrs
Many-pointers are also not single-pointers and wouldn't be considered
here. This commit makes the conditions use the appropriately-named
isSinglePointer instead.
* Sema: Correctly obtain ArrayInfo for many-pointer concatenation
Many-pointers at comptime have a known size like slices and can be used
in array concatenation. This fixes a stage1 regression.
* test: Add comptime manyptr concatenation test
Co-authored-by: sin-ack <sin-ack@users.noreply.github.com>
032c722d20