stage3-release does not pass the new reify fn test case

[andrewrk]

This issue can be closed when the CI additionally has behavior test coverage for stage3-release.

$ stage3-release/bin/zig test ../test/behavior.zig -I../test
Test [1144/1343] test.Type.Fn... expected type fn(c_int, *behavior.type.test.Type.Fn.some_opaque) callconv(.C) void, found type fn(c_int, *behavior.type.test.Type.Fn.some_opaque) callconv(.C) void
Test [1144/1343] test.Type.Fn... FAIL (TestExpectedEqual)
1252 passed; 90 skipped; 1 failed.

This was working a few weeks ago, so a git bisect should be able to find when this broke.

zig/test/behavior/type.zig

Lines 512 to 542 in 50b36e8

	test "Type.Fn" {
	if (builtin.zig_backend == .stage1) return error.SkipZigTest;
	if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
	const some_opaque = opaque {};
	const some_ptr = *some_opaque;
	const T = fn (c_int, some_ptr) callconv(.C) void;
	{
	const fn_info = std.builtin.Type{ .Fn = .{
	.calling_convention = .C,
	.alignment = 0,
	.is_generic = false,
	.is_var_args = false,
	.return_type = void,
	.args = &.{
	.{ .is_generic = false, .is_noalias = false, .arg_type = c_int },
	.{ .is_generic = false, .is_noalias = false, .arg_type = some_ptr },
	},
	} };
	const fn_type = @Type(fn_info);
	try std.testing.expectEqual(T, fn_type);
	}
	{
	const fn_info = @typeInfo(T);
	const fn_type = @Type(fn_info);
	try std.testing.expectEqual(T, fn_type);
	}
	}

[andrewrk]

git bisect points to 292906f where the test was first introduced (#12312). I don't think it was ever passing for a release build of stage3