[Gate Tests] - marking feature tests

Removal of the lang feature gate tests whitelist #39059

r? @est31

Author: cseale

src/test/compile-fail-fulldeps/gated-macro-reexports.rs

@@ -11,6 +11,7 @@
 // Test that macro reexports item are gated by `macro_reexport` feature gate.
 
 // aux-build:macro_reexport_1.rs
+// gate-test-macro_reexport
 
 #![crate_type = "dylib"]
 

src/test/compile-fail-fulldeps/gated-quote.rs

@@ -15,6 +15,8 @@
 
 // FIXME the error message that is current emitted seems pretty bad.
 
+// gate-test-quote
+
 #![feature(rustc_private)]
 #![allow(dead_code, unused_imports, unused_variables)]
 

src/tools/tidy/src/features.rs

@@ -166,8 +166,7 @@ pub fn check(path: &Path, bad: &mut bool) {
 
     // FIXME get this whitelist empty.
     let whitelist = vec![
-        "abi_ptx", "simd", "macro_reexport",
-        "static_recursion", "quote",
+        "abi_ptx", "simd", "static_recursion",
         "cfg_target_has_atomic", "staged_api", "const_indexing",
         "unboxed_closures", "stmt_expr_attributes",
         "cfg_target_thread_local", "unwind_attributes",