Replace CArray by CPointer (#406)

Also do some cleanup.

backend.native/tests/interop/basics/3.kt

@@ -11,7 +11,7 @@ fun main(args: Array<String>) {
         values[3].value = 13
         values[4].value = 8
 
-        cstdlib.qsort(values[0].ptr, count.toLong(), CInt32Var.size, staticCFunction(::comparator))
+        cstdlib.qsort(values, count.toLong(), CInt32Var.size, staticCFunction(::comparator))
 
         for (i in 0 .. count - 1) {
             print(values[i].value)

backend.native/tests/interop/basics/echo_server.kt

@@ -35,14 +35,14 @@ fun main(args: Array<String>) {
                 .ensureUnixCallResult { it >= 0 }
 
         while (true) {
-            val length = read(commFd, buffer.ptr, bufferLength)
+            val length = read(commFd, buffer, bufferLength)
                     .ensureUnixCallResult { it >= 0 }
 
             if (length == 0L) {
                 break
             }
 
-            write(commFd, buffer.ptr, length)
+            write(commFd, buffer, length)
                     .ensureUnixCallResult { it >= 0 }
         }
     }