samples: add Terra samples

source: https://github.com/zdevito/terra/tree/master/tests

samples/Terra/teststd.t

@@ -0,0 +1,45 @@
+local S = require "std"
+
+c = global(int,0)
+
+struct A(S.Object) {
+    a : int;
+    b : int[5];
+}
+struct C {
+    a : int
+}
+struct B(S.Object) {
+    a : A;
+    b : A[2];
+    c : C[3];
+    c2 : C;
+    c3 : C[2];
+}
+
+terra A:__destruct()
+    S.printf("A dtor!\n")
+    c = c + 1
+end
+terra B:__destruct()
+    c = c + 10
+end
+terra foo()
+    var a = A.salloc()
+end
+
+foo()
+assert(c:get() == 1)
+
+terra bar()
+    var b = B.salloc()
+end
+bar()
+assert(c:get() == 14)
+
+terra baz()
+    var b = B.alloc()
+    b:delete()
+end
+baz()
+assert(c:get() == 27)