[lldb] Include unistd.h for sleep in profile_vrs_detach

(cherry picked from commit 08f4b56)

Author: JDevlieghere

lldb/test/API/macosx/profile_vrs_detach/main.c

@@ -1,10 +1,11 @@
 #include <stdio.h>
+#include <unistd.h>
 
 int
 main()
 {
   while (1) {
-    sleep(1); // Set a breakpoint here 
+    sleep(1); // Set a breakpoint here
     printf("I slept\n");
   }
   return 0;