Add ada test program for ada tasks.

tests/helloadatasks/helloadatasks.adb

@@ -0,0 +1,53 @@
+
+----------------------------------------------------------
+--  This three-task program includes the main procedure,
+--  helloadatasks, as the "main task" and two tasks, Task_A and
+--  Task_B, nested inside it.
+----------------------------------------------------------
+
+with Ada.Text_IO, Ada.Calendar;
+use  Ada.Text_IO, Ada.Calendar;
+
+procedure helloadatasks is
+
+  Start_Time   : constant Time := Clock;
+  Elapsed_Time : Duration;
+
+  task Task_A is
+    entry Go;
+  end Task_A;
+
+  task Task_B is
+    entry Go;
+  end Task_B;
+
+  task body Task_A is
+  begin
+    delay 2.0;                           -- relative delay
+    accept Go;
+    Elapsed_Time := Clock - Start_Time;
+    Put_Line("helloadatasks/Task_A Rendezvous occurred at T = "
+             & Integer'Image(Integer(Elapsed_Time)));
+    for I in 1..5 loop
+      delay 2.0;                         -- relative delay
+      Task_B.Go;
+    end loop;
+  end Task_A;
+
+  task body Task_B is
+  begin
+    for I in 1..5 loop
+      delay until (Start_Time + I*7.0);  --absolute delay
+      accept Go;
+      Elapsed_Time := Clock - Start_Time;
+      Put_Line("Task_A/Task_B Rendezvous occurred at T = "
+               & Integer'Image(Integer(Elapsed_Time)));
+    end loop;
+  end Task_B;
+
+begin
+
+  Task_A.Go;
+
+end helloadatasks;
+