zig test --test-evented-io is broken

[slimsag]

With a basic async example:

const std = @import("std");
const expect = std.testing.expect;

var x: i32 = 1;

test "suspend with no resume" {
    var frame = async func();
    try expect(x == 2);
    _ = frame;
}

fn func() void {
    x += 1;
    suspend {}
    // This line is never reached because the suspend has no matching resume.
    x += 1;
}

It fails to compile under zig test --test-evented-io:

$ zig test --test-evented-io main.zig 
/Users/slimsag/Desktop/hexops/zig/build/lib/zig/std/special/test_runner.zig:59:42: error: expected type 'void', found 'std.mem.Allocator.Error'
                    async_frame_buffer = try std.heap.page_allocator.alignedAlloc(u8, std.Target.stack_align, size);
                                         ^
/Users/slimsag/Desktop/hexops/zig/build/lib/zig/std/special/test_runner.zig:19:15: note: function cannot return an error
pub fn main() void {
              ^

[slimsag]

PR incoming!