Remove notice from Strassen Multiplication Matrix playground

Author: imvm

Strassen Matrix Multiplication/StrassensMatrixMultiplication.playground/Contents.swift

@@ -1,10 +1,5 @@
 //: Playground - noun: a place where people can play
 
-// last checked with Xcode 9.0b4
-#if swift(>=4.0)
-print("Hello, Swift 4!")
-#endif
-
 import Foundation
 
 var A = Matrix(rows: 2, columns: 4, initialValue: 0)