samples: add Terra samples

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

samples/Terra/goto2.t

@@ -0,0 +1,18 @@
+
+local begin = symbol()
+local theend = symbol()
+
+terra foo()
+	var a = 0
+	::[begin]::
+	if a >= 10 then
+		goto [theend]
+	end
+	a = a + 1
+	goto [begin]
+	::[theend]::
+	return a
+end
+
+test = require("test")
+test.eq(foo(),10)