Deduplicate ui-fulldeps.

Author: cjgillot

src/test/ui-fulldeps/hash-stable-is-unstable.rs

@@ -1,5 +1,5 @@
 // ignore-stage1
-
+// compile-flags: -Zdeduplicate-diagnostics=yes
 extern crate rustc_data_structures;
 //~^ use of unstable library feature 'rustc_private'
 extern crate rustc_macros;

src/test/ui-fulldeps/lint-tool-test.stderr

@@ -83,11 +83,6 @@ error: item is named 'lintmetoo'
 LL |     fn lintmetoo() { }
    |     ^^^^^^^^^^^^^^^^^^
    |
-note: the lint level is defined here
-  --> $DIR/lint-tool-test.rs:14:9
-   |
-LL | #![deny(clippy_group)]
-   |         ^^^^^^^^^^^^
    = note: `#[deny(clippy::test_group)]` implied by `#[deny(clippy::group)]`
 
 warning: lint name `test_group` is deprecated and may not have an effect in the future.