[Gate Tests] - marking feature tests

[cseale]

Removal of the lang feature gate tests whitelist #39059

r? @est31

[est31]

@cseale you should remove those tests from the whitelist:

rust/src/tools/tidy/src/features.rs

Lines 168 to 175 in 6fe2371

	"abi_ptx", "simd", "safe_suggestion", "macro_reexport",
	"more_struct_aliases", "static_recursion", "reflect",
	"quote", "cfg_target_has_atomic", "custom_attribute",
	"default_type_parameter_fallback", "pushpop_unsafe",
	"use_extern_macros", "staged_api", "const_indexing",
	"unboxed_closures", "stmt_expr_attributes",
	"cfg_target_thread_local", "unwind_attributes",
	"inclusive_range_syntax"

[cseale]

@est31 done

[eddyb]

@bors r=est31

[bors]

📌 Commit ddb6027 has been approved by est31

[bors]

⌛ Testing commit ddb6027 with merge a8fa310...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: est31
Pushing a8fa310 to master...

[est31]

Its merged. Thanks @cseale !