Remove #[simd_test] support

This attribute is a procedural macro defined by the crate
simd-test-macro, not a built-in macro.

gcc/rust/ChangeLog:

	* util/rust-attribute-values.h (Attributes::SIMD_TEST): Remove
	static constexpr member variable.
	* util/rust-attributes.cc (__definitions): Remove entry for
	SIMD_TEST.

Signed-off-by: Owen Avery <[email protected]>

Author: powerboat9

gcc/rust/util/rust-attribute-values.h

@@ -88,8 +88,6 @@ class Attributes
 
   static constexpr auto &TEST = "test";
 
-  static constexpr auto &SIMD_TEST = "simd_test";
-
   static constexpr auto &RUSTC_ARGS_REQUIRED_CONST
     = "rustc_args_required_const";
 };

gcc/rust/util/rust-attributes.cc

@@ -126,7 +126,7 @@ static const BuiltinAttrDefinition __definitions[]
      {Attrs::RUSTFMT, EXTERNAL},
 
      {Attrs::TEST, CODE_GENERATION},
-     {Attrs::SIMD_TEST, CODE_GENERATION}};
+};
 
 BuiltinAttributeMappings *
 BuiltinAttributeMappings::get ()