Remove related tests

Author: JohnTitor

src/test/ui/feature-gates/feature-gate-infer_static_outlives_requirements.rs

@@ -1,7 +1,5 @@
 /*
- * We don't infer `T: 'static` outlives relationships by default.
- * Instead an additional feature gate `infer_static_outlives_requirements`
- * is required.
+ * We don't infer `T: 'static` outlives relationships.
  */
 
 struct Foo<U> {

src/test/ui/feature-gates/feature-gate-infer_static_outlives_requirements.stderr

@@ -1,11 +1,11 @@
 error[E0310]: the parameter type `U` may not live long enough
-  --> $DIR/dont-infer-static.rs:8:10
+  --> $DIR/dont-infer-static.rs:6:10
    |
 LL |     bar: Bar<U>
    |          ^^^^^^ ...so that the type `U` will meet its required lifetime bounds...
    |
 note: ...that is required by this bound
-  --> $DIR/dont-infer-static.rs:10:15
+  --> $DIR/dont-infer-static.rs:8:15
    |
 LL | struct Bar<T: 'static> {
    |               ^^^^^^^