test: remove package-wide import assumptions

test/wcc/data/r75_alloc_two_str/case.ww

@@ -1,5 +1,4 @@
 //ww:run-exit 9
 package main;
-import rt;
 type holder = struct { a: str, b: str };
 fn main() i32 = { let p: *holder = alloc(holder { a = "foo", b = "barbaz" })!; return p.a.len + p.b.len; };