[all] only apply size preallocation on MD5 for neko, c#, java and C++

std/haxe/Md5.hx

@@ -95,7 +95,9 @@ class Md5 {
 		
 		//preallocate size
 		var blksSize = nblk * 16;
+		#if (neko || cs || cpp || java)
 		blks[blksSize - 1] = 0;
+		#end
 		
 		#if !(cpp || cs) //C++ and C# will already initialize them with zeroes.
 		for( i in 0...blksSize ) blks[i] = 0;