samples: add Terra samples

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

samples/Terra/quote5.t

@@ -0,0 +1,20 @@
+
+c = global(0)
+terra foo(a : int)
+    c = c + a
+end
+
+local stmts = quote
+    foo(5)
+    foo(6)
+    foo(7)
+end
+
+local stmts2 = {stmts,stmts}
+terra doit()
+    stmts
+    stmts2
+    return c
+end
+local test = require("test")
+test.eq(doit(),54)