samples: add Terra samples

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

samples/Terra/offsetcalc.t

@@ -0,0 +1,33 @@
+local offsetinbytescache = {}
+function offsetinbytes(structtype,key)
+    local typetable = offsetinbytescache[structtype] or {}
+    local value = typetable[key]
+    if value then
+        return value
+    end
+    offsetinbytescache[structtype] = typetable
+    
+    local terra offsetcalc() : int
+        var a : &structtype = [&structtype](0)
+        return [&int8](&a.[key]) - [&int8](a)
+    end
+    
+    local result = offsetcalc()
+    
+    typetable[key] = result
+    return result
+end
+
+
+struct A { a : int8, c : int8, b : int }
+
+
+terra foo()
+	return 4LL
+end
+
+local test = require("test")
+
+test.eq(offsetinbytes(A,"b"),4)
+
+