remove unnecessary test

tests/ui/traits/next-solver/temporary-ambiguity.rs

@@ -1,22 +0,0 @@
-// compile-flags: -Znext-solver
-// check-pass
-
-// Checks that we don't explode when we assemble >1 candidate for a goal.
-
-struct Wrapper<T>(T);
-
-trait Foo {}
-
-impl Foo for Wrapper<i32> {}
-
-impl Foo for Wrapper<()> {}
-
-fn needs_foo(_: impl Foo) {}
-
-fn main() {
-    let mut x = Default::default();
-    let w = Wrapper(x);
-    needs_foo(w);
-    x = 1;
-    let _ = x;
-}