Issue Description:

I was playing around with profiling benchmarks (Suffix.swift) and I’ve noticed that for large N, the tight loops were dominated by String interpolation instead of whatever the test was supposed to test. It looks like the CheckResults function always constructs the error message.

public func CheckResults(_ res: Bool, _ message: String = ""){
    if res {
        return
    }
    print(message)
    abort()
}

I guess we should redefine it with @autoclosure:

public func CheckResults(_ resultsMatch: Bool, _ message: @autoclosure () -> String){
    guard resultsMatch else {
        print(message())
        abort()
    }
}

I’ve taken the liberty to remove default value for message, all existing tests provide it and aborting without it is not very useful anyway.