fix: minor issues with CI

* update ctor

* pass empty `RUSTFLAGS` when installing cross, overriding
the default `-D warnings`

* fix some clippy lints

* create `target` directory before curling wasmtime lib

cli/src/test_highlight.rs

@@ -171,7 +171,7 @@ pub fn iterate_assertions(
             // position, looking for one that matches the assertion.
             let mut j = i;
             while let (false, Some(highlight)) = (passed, highlights.get(j)) {
-                end_column = (*position).column + length - 1;
+                end_column = position.column + length - 1;
                 if highlight.0.column > end_column {
                     break 'highlight_loop;
                 }