test logical short-circuit cases (#27)

tests/lua-5.3/logical_operations.lua

@@ -0,0 +1,6 @@
+local x = nil
+local x_ = (x and x.k or "fallback")
+assert(x_ == "fallback")
+local y = "ok"
+local y_ = (y or error("should not raise"))
+assert(y == y_)

tests/test.js

@@ -24,6 +24,7 @@ let exitCode = 0
     })
     luaEnv.parseFile('goto.lua').exec()
     luaEnv.parseFile('bwcoercion.lua').exec()
+    luaEnv.parseFile('logical_operations.lua').exec()
 }
 
 {