Merge #1162 #1167 #1168 #1170

1162: CI: catch malformed test cases r=philberty a=liushuyu

- catch malformed test cases and use GitHub Actions' annotation feature to mark the failures

1167: Fix nullptr when resolving the root of a path expression r=philberty a=philberty

When we resolve paths we don't have a _type_, in this scenario there is a
bug in our resolution of this generic function so this means the root_tyty
is nullptr but the offset is non zero so we return nullptr.

Addresses #1132

This test case no longer ICE's but still fails. I have a fix in progress for this

```rust
mod mem {
    extern "rust-intrinsic" {
        fn transmute<U, V>(_: U) -> V;
    }
}

pub trait Hasher {
    fn write(&mut self, bytes: &[u8]);
    fn write_u16(&mut self, i: u16) {
        self.write(&mem::transmute::<_, [u8; 2]>(i))
    }
}

pub struct SipHasher;

impl Hasher for SipHasher {
    #[inline]
    fn write(&mut self, msg: &[u8]) {}
}

```

1168: ast: resolve: Move ResolveItem into its own source file r=CohenArthur a=CohenArthur

Since we need to add new functions to resolve visibilities, we might as well refactor this file before hand :) 

1170: Implement macro expansion in `IfExpr`, `IfExprConseqElse`, `IfExprConseqIf`, `IfExprConseqIfLet`. r=CohenArthur a=antego

Addresses #1141. Following up on #1161.

This change adds support for the macros inside the `if` condition expressions.

Things to note:
1. Judging by my research, the `IfExprConseqIfLet` isn't used. The parser treats the syntax `let var = if ...` as a `let` expression followed by `if` expression:
![Screen Shot 2022-04-26 at 9 47 29 am](https://user-images.githubusercontent.com/1451467/165258060-6a42f918-2585-4aef-9da5-9d60d69ca248.png)
2. I didn't add the macro expansion to the `IfLetExpr...` family of expressions because I wasn't able to write a test case reproducing the missing macro expansion. I've tried the following code
```rust
fn main() -> i32 {
    let mut res = 0;

    enum E {
        X(u8),
        Y(u8),
        Z(u8),
    }
    let v = E::Y(12);
    if let E::Y(n) = v {
        res = 1;
    }

    0
}
```
which caused the compiler error
```
FAIL: rust/compile/macro43.rs (internal compiler error: in append_reference_for_def, at rust/resolve/rust-name-resolver.h:227)
```



Co-authored-by: liushuyu <liushuyu011@gmail.com>
Co-authored-by: Philip Herron <philip.herron@embecosm.com>
Co-authored-by: Arthur Cohen <arthur.cohen@embecosm.com>
Co-authored-by: antego <antego@users.noreply.github.com>